All the collies I've had (4) have in varying degrees been irrationally frightened of something, ranging from people with walking sticks or Zimmer frames who walk hunched over but not those who walk straight up, little children, strong winds etc, but all have been scared of loud noises, I read somewhere that it is a breed characteristic that they can develop these fears and its do with them being bread to be obsessed with things I.e sheep, mind my second collie, jess, was scared of sheep at first, IMO is cos they're so clever,
I once had a horse that was scared of puddles - that's pretty irrational too, so it's not just dogs, and I'm scared of cows and wasps as well