Then there's online dating and dating in general. You are contacting someone and spending time with someone in the hopes of (eventual) love or sex or marriage. Going in with expectations is tricky. You expect (or hope) it to go a certain way and it probably won't.
And then you get aggravated and post a Facebook status like this:
The gap between expectations and reality is unfortunately large. This, boys and girls, is called disappointment.(Sarcasm, bitterness and surprising insight, all rolled into one.)
Just another thing to approach in life with an open mind. Who knows where it'll lead you?