Commitment. Let me tell you something about it. If a person make plans with someone else and then later on can't make it for whatever reason, they should take the initiative to call/text/write to say they are unable to show up. If they don't (especially if I happen to see them on facebook that same night.), then they're a total douche bag. Never ever keep a friend waiting. Especially when they work to make sure that nothing else is planned on that day. If you keep them waiting and never say or write anything, then that friend's day is completely wasted. So in other words, don't be a lazy, inconsiderate turd and learn to communicate. Because if you don't, then you may eventually not have any friends left to hang out with.