It's something we do over time - take the most important people in our lives for granted. We reach a point where we understand that we're in too deep to leave each other, and maybe that gives us permission to treat the other person poorly. We assume their loyalty gives us a free pass to take advantage of their good qualities, of their feelings, of the way they stay in our lives no matter how deeply we hurt them. We think it's okay to stop making an effort for them it's okay to use them as a punching bag, it's okay to reach out to them only when we need them and not the other way around. It's one of the worst human traits - to not realise what we have until it's gone. Because one day, this person will reach the end of their patience and tolerance for you. They will get up and leave. And it's only then that you will see that you had it all, but you just didn't value it enough.