Used to be my worst fears too! Clowns still are--they are not to come within visual distance of me or I will freak out and possibly run them over with a car.
Uhh, the past summer my neighbors were doing work on their house and a large amount of GIANT FLYING COCKROACHES somehow made their merry way over to our house. Our cats had a ball catching them but the first time I saw one (no one else was home) I just stood there for ten minutes screaming wordlessly and soundlessly--I was so scared I lost my voice... the second time they got one it was 5 minutes and less and less as time went by. Now I've got no problem with them. Talk about flooding.
My grandmother was deathly afraid of snakes and she refused to come over to our house after she found out I got one (we lived like 2 blocks from her.)
(I didn't realize so many people thought all snakes are venomous--that kind of blows my mind.)