I think my only irrational fear is my fear of heights. Planes don't bother me (so long as they stay up there) but tall bridges and buildings terrify me.

Snakes and bugs don't bother me and, although I used to be arachnophobic, I trained myself not to be because spiders are generally beneficial and are highly respected in some Native American cultures. I never had a reason to train myself out of my acrophobia, though.

I have a plethora of 'rational fears', though, so let me know when you get to those. ;)