The role of a parent is supposed to be selfless, but some turn out to be anything but. In fact, they start to feel like their kids owe them something after they have raised them for however many years.
While it may be true that there are adult children out there who use their parents in a way that is entitled and unacceptable, the same can be said of certain parents towards their kids. Some people have the kind of personality where they see procreation as another opportunity to sponge off of somebody. It might not be pleasant, but it is not an uncommon phenomenon that certain individuals have the displeasure of dealing with.