A little Arab mare I rode and showed in HJ was scared of a trash can. However, the can had not been moved, cleaned, or anything for at least two years, during which she passed the can at least twice a day. Weird!
My boy now is scared to death of cows. He hears a “Moo” and his eyes roll and he has a high speed come apart. Needless to say, he is not a roping horse.