Part of acclimating children for their future roles as adults who will find themselves saying the same words their parents said to them despite the protestations that they'll never be like us is, indeed, training them in the art of doing those have-tos without bitching about the not-fairs. It's not an easy task, by any means, but it is absolutely vital that we teach them while they are young.
I often joke with my students that the new tech of today's world means that one can reach adulthood and never learn to tie a shoe, zip pants, fasten a button, drink from a cup or use a fork and knife. Add to that, we can buy single serving drinks and meals so that our children never learn to pour from a jug, never learn how to dish food out, never learn how to cook, and in the process we've managed to set ourselves up as parents for a continued dependency for our children. The mental image of Lily going on a date and not being able to eat at a real restaurant or a traditional family meal spurred me to make sure that these are skills all the children have. "I'm sorry, Mom, I know I'm capable of living independently, but you didn't teach me how to dish food out or drink out of a cup." Not on my watch.
Whether our children have no issues (they all have issues), some issues, or a multitude of issues that work to significantly impair them, it is our job as parents to teach them that life is messy, that learning to do something well means work and regular practice, that some things aren't have-tos but matter enough that they are gotta-dos, and how to distinguish between the two, and perhaps most of all, that life isn't fair, but it's our job to work to equalize the truly not-fairs, especially when what our children mean by not fair is that they're annoyed they've got a have-to a sibling doesn't have.