Yeah, my bud always uses this reference in cases like these...it's from some movie which the name escapes me but it's pretty much up there with Duti's insightful wisdom.
"He took 20 bucks from me and said he'd pay me back. Now he avoids me."
"Well...think of it this way. For 20 dollars, you won't have to see him ever again. I think that you're better off."
That's what sucks about life. You never truly know most of the people you think you do. Least not til the moment of truth arises. The problem with situations like these is you can't let them guide you in regards to your real friends. A lesson learned? Yes. But don't let it ruin what could be great friendships with people you've yet to meet. But also...don't let your mind forget it.
There's friends...and then there's aquaintences. It pays to know the difference.