It's interesting how life is always a surprise. The people I meet who are actually worth knowing are very rarely the ones whom I think that would be the case for when I first meet them. It always sneaks up on me, and then suddenly I'll realize one day that they are enormous pieces of my life and that I learn so much from them. On the other hand, the people who I meet and assume would be worth knowing and worth trusting, are usually the ones who are pros at letting me down, at abandoning friendships when they are needed most. Happens to me so frequently.
The one thing it has taught me is to definitely not just assume anything when first meeting someone.