Think about the last three times you became upset about something in your personal life.  It's almost a certainty that at least one of those situations was caused by the fact that your limits were crossed.  You probably didn't articulate those limits in advance.  For example, your neighbor comes over unannounced to chat.  You have only a few minutes to spare, but you fail to tell your visitor.  Out of kindness, you listen while your blood pressure rises as the neighbor talks for an hour.  

-Michael C. Donaldson, Negotiating for Dummies

You've heard that "good fences make good neighbors."  As Michael C. Donaldson points out, it is these clear boundaries that makes that aphorism ring true.  But what if we forgot to build the fence in the first place?  This is the crux of today's tip: we shouldn't get mad at someone for stepping over boundaries we've never set or communicated.

If it's that simple, then why don't we just set clear limits?  Well, there are many reasons, most of which center on us feeling like it's not polite.  But if we realize that what's truly impolite (and frankly unfair) is to be frustrated with someone for something that isn't their fault, we can move past the momentary awkwardness and just start communicating.  We might even find that it's actually not uncomfortable at all once we start to practice it.

So try it out beginning immediately, either in your work or personal life (or both).  Start with a very simple situation like Michael C. Donaldson's example, where you only have limited time for something or someone.  Mention your time frame right at the beginning, being sure to say something to reaffirm your interest like, "I'm definitely dedicated to helping you with X, but I currently have only about 20 minutes to give."  Then, once that time is up, restate your interest in some way and then set up a future time to reconnect.  Following this process ensures that you are still very polite and receptive to the other person, but builds a simple and clear boundary to protect your needs.