What's the hardest part about being a parent?

Lot of good answers here. For me hardest part about being a parent is making choices. You are not independent any more. You have to choose whether to go out with friends/go for a movie that you don't wanna miss and leave your child with nanny or skip the party/movie to spend time with your child. Sometimes you just want some timeout or break from your routine but it's not possible. You have to adjust your entire schedule around the kids and that change might be taxing for some parents.