I have an irrational fear...quite a rare one. It's a form of dendrophobia...which is a blanket term for a fear of trees. But in my case, a very specific type of tree. Basically I can't touch pine trees (coniferous trees) because I hate the feeling...had it since I was a very small child and don't really know how it came about. It doesn't impact my daily life but even 20 years later I still can't get within a few meters of a pine tree without feeling jumpy. It was an issue when I was younger and we had a real tree at christmas.
It sounds really weird (most irrational fears are). I know some may think it's ridiculous and you're right it is. I've never really told anyone about it but since you asked I don't think I'll ever get over it but I'm not fussed.