Even when I worked out of the home, I felt guilty asking for time off for an appointment or whatever else. I think for some of us, it's just who we are! We are hired for a job and we want to fulfill that to the best of our ability.
I don't ask the parents for time off, I just tell them well in advance if I am closing for whatever reason. It doesn't mean I don't feel bad about it though. I try not to feel guilty about because we all deserve time off and I'm getting better about not feeling guilty but I do a bit because I know it's an inconvenience for them. During interviews, I make it very clear that they need to have a backup or a plan in place for when I am closed. This helps me not feel so guilty because I know they have a grandparent, aunt, uncle etc that they can use when I'm closed.