Both are speculation, regardless. Maybe you met a right person at the wrong time for one of you, maybe they were incapable of dealing with it, too. *shrug* Past can't be changed, best look at the future :)

Behaviour: If that's the actual cause, yes, but even then it can't be the entire cause. (If it was, you would notice a distinct lack of friends!)

It's a very silly movie, but does have that quote halfway through it :) And it has a nice fairy tale ending.