Complex human behaviors

Every puzzle fails when compared to the puzzling human behavior

Many a times I am left wondering why people who have been quite friendly with you in the past behave in a strange manner that you'll never ever understand. Even if you try to.. it's futile ! Today I kinda faced similar situation and cuz of my typical cancerian nature got a bit disturbed with that.

You entrust somebody with a job simply cuz you've faith on that person who happens to be a supposedly good friend of yours,..now one fine day you wake up to realize that, that very person acts in a very unpredictable and a not-so-friendly manner( indirectly though) and you're left with scratching your head that what went wrong..what did I do..?

Here when people complicate trivial things, blow things up out of proportions and cause problems out of it, the chain continues and in the end its the both sides who are at loss I must say and to that a good rapport gets lost in no time.
What I don't understand is if you' happen to be a good friend of some person and you're having some kinda issue with him, why not sort it out at once. Give him a slap or two and tell him upfront whatever problems you had with him. Thats how friends are supposed to be. There's no point in ruining the relation and making it bitter at once when you've had great time together and with all your friends in the past.

Its just that sometimes human behaviours are too tough to fathom which keep us puzzling all through the day without getting a slightest clue about its reason, not to mention they leave you hurt too.