I have to believe that every dog that any of us has ever owned had at least one thing that frightened them. Storms, the vet, men (lol, I've seen that mentioned here many times!), vehicles, firecrackers, guns, chainsaw or other tools, Etc. Even if you think your dog is brave there might be one little thing that they're not really sure about.
For Kali the main thing is thunder. I don't even remember when it started. And sometimes I wonder if it wasn't perpetrated by me. I mean, I'm not terrified in storms unless they're really, really bad. But when you think about what you do in a storm I can imagine that they feel that anxiety. Say a sudden storm pops up... you're running around closing windows, yelling to each other, going outside and strapping things down or bringing them inside. All that sudden/fast activity that they see comes across as, What's happening!?!?
So that may have been what started it, I'll never be sure. But there are times when it is bad outside and she is just trembling! And half the time it's at night time. If it was during the day I might try and play with her to distract her.
But, alas, it's usually at night and the most I can do is take her in bed with me. Sometimes I put her under the covers so she doesn't see the lightning.
But it doesn't help much.
But I do know what started her fear of a certain beep.
Several years ago my husband and I picked up a new weather station and this one detected lightning! We thought it was pretty cool. So once it was installed it would send a beep to the weather station when it detected lightning and of course thunder. It would detect it far enough away that you wouldn't even hear it until it got closer.
Well, since this little one is afraid of lightning and thunder, she associated that tone with the accompanying thunder.
Makes perfect sense doesn't it?
Well, we eventually took out the lightning detector.
And then one day the grandkids were here with a tiny little handheld drone that we bought them for Christmas. Well, it turned out that thing sounded a little beep just like the lightning detector whenever they started it. Kali was acting so strange. Clinging to me, tail down, finally even going upstairs to be with my daughter! She was up there getting dressed and she texted me telling me that Kali was up there with her which was very unlike her. She would never do that. I finally connected the dots
and realized what was happening. I told the kids they had to play that drone downstairs in the basement.
After that I was always aware of something making the same type of beep and I knew she would react. It's almost the same kind of beep that's on your microwave. But she doesn't react to that.
Maybe shes gotten used to that.
But there's a couple of other things that do have the same beep. One of them is my diffuser! Ugh. I find every time I turn it on, she leaves the room. Sigh. Even if I just start messing with it. Filling the water, anything. Sometimes she just looks at me like, "What the hell, mom? Are you going to put that thing on again?" And then when I press the on button, she slowly walks away. SMH I'm not sure how to undo that training. Except to just keep doing it. I have tried to give her some treats at the same time I'm pressing the button. She's done fairly well with that. And I probably will just continue that. Maybe with some really yummy treats that she can't resist.
Or I was thinking about when the grandkids are here that they can be playing with her, again with some yummy treat that she can't resist, while I press the button. Otherwise she's just going to have to leave the room! 
One of the other things she hates are snakes. That's a good one to be afraid of! But I noticed it years ago when I was trying to show the grandkids a snake. It was just a bull snake but they make a sound by breathing in and out that is just a big Sssssss sound. I noticed her keeping her distance and realized she knew that that was a snake by that sound and she didn't like it.
Well, the other thing that makes a similar sound is our air compressor in my husband's barn. She hates when that thing goes on because she knows the hose makes that Sssssssss sound. And God forbid you let the air out! I even hate that sound! It's so damn loud. He's got airlines going all the way out to my horse barn and when he's filling my tires in my barn she just keeps a wide berth!
So those are the only 2 things I can think of right now that I know she's afraid of. Other than that she's a pretty tough little dog.

How about your dog(s)? Tell us a story about their fears.
For Kali the main thing is thunder. I don't even remember when it started. And sometimes I wonder if it wasn't perpetrated by me. I mean, I'm not terrified in storms unless they're really, really bad. But when you think about what you do in a storm I can imagine that they feel that anxiety. Say a sudden storm pops up... you're running around closing windows, yelling to each other, going outside and strapping things down or bringing them inside. All that sudden/fast activity that they see comes across as, What's happening!?!?
So that may have been what started it, I'll never be sure. But there are times when it is bad outside and she is just trembling! And half the time it's at night time. If it was during the day I might try and play with her to distract her.
But, alas, it's usually at night and the most I can do is take her in bed with me. Sometimes I put her under the covers so she doesn't see the lightning.
But I do know what started her fear of a certain beep.
Well, since this little one is afraid of lightning and thunder, she associated that tone with the accompanying thunder.
Well, we eventually took out the lightning detector.
And then one day the grandkids were here with a tiny little handheld drone that we bought them for Christmas. Well, it turned out that thing sounded a little beep just like the lightning detector whenever they started it. Kali was acting so strange. Clinging to me, tail down, finally even going upstairs to be with my daughter! She was up there getting dressed and she texted me telling me that Kali was up there with her which was very unlike her. She would never do that. I finally connected the dots
and realized what was happening. I told the kids they had to play that drone downstairs in the basement.After that I was always aware of something making the same type of beep and I knew she would react. It's almost the same kind of beep that's on your microwave. But she doesn't react to that.
But there's a couple of other things that do have the same beep. One of them is my diffuser! Ugh. I find every time I turn it on, she leaves the room. Sigh. Even if I just start messing with it. Filling the water, anything. Sometimes she just looks at me like, "What the hell, mom? Are you going to put that thing on again?" And then when I press the on button, she slowly walks away. SMH I'm not sure how to undo that training. Except to just keep doing it. I have tried to give her some treats at the same time I'm pressing the button. She's done fairly well with that. And I probably will just continue that. Maybe with some really yummy treats that she can't resist.
Or I was thinking about when the grandkids are here that they can be playing with her, again with some yummy treat that she can't resist, while I press the button. Otherwise she's just going to have to leave the room! Well, the other thing that makes a similar sound is our air compressor in my husband's barn. She hates when that thing goes on because she knows the hose makes that Sssssssss sound. And God forbid you let the air out! I even hate that sound! It's so damn loud. He's got airlines going all the way out to my horse barn and when he's filling my tires in my barn she just keeps a wide berth!
So those are the only 2 things I can think of right now that I know she's afraid of. Other than that she's a pretty tough little dog.
How about your dog(s)? Tell us a story about their fears.
even if it doesn't thunder. I have CBD oil I give her if I know a storm is coming....doesn't help too much though. We have alot of people shooting in the distance around here, and if we are out in our woods; she will come back to me, and be glued to me the rest of our walk. Clarke never minded the thunder, or gunfire, BUT, hated the sound of me putting away cookie sheets!!! All I had to do was open the cabinet they were in, and he would run to another room, and peek back at me!
. He also didn't like when we would scoop ice out of the ice drawer in the freezer. So odd. A female we had back in 2009 didn't like the sound of shaking out blankets when making the bed!!!