My biggest phobia is the fear of something happening to one of my pets, Vixen especially. I know where it came from. It all started when we lost Lilith in 2005. We nor the vet knew there was anything wrong with her. Actually just a month before her passing she got a clean bill of health. She got a rabies shot for travel to Italy and we having what we thought was a reaction but was not. It was actually a cancer from FeLv and the shot dropped her system allowing the cancer to take over. From the day of the shot to the day of her death was 8 days. I guess you can see where that phobia would play through as Vixen is FeLv+ as well.

Habits...biting the skin on my fingers - habit from when I was a child.
....have to eat my pizza with a fork and knife
....have to always have a flashlight close by - habit learned from my
mom
....walking barefoot even though I am not suppose to because I'm
diabetic
....shower habit...have to wash my hair twice then condition before I
actually clean my body

I am sure there are others too.