huckleberry and JackAce have the best answers to your question, but I'd like to add one important detail. (and a response to part of what you asked.)
IT DOESN'T MATTER!
WHY??? WHY did you toss that Queen-7 off-suit??? You tossed it because you're trying to become a GOOD poker player! Who cares if a Queen-7-3 comes on the flop?!?
The biggest reaction that should get from you is the tiniest chuckle inside your head.
Ever hear the expression, "Any two cards"? Any two cards can win any given hand. If you played EVERY hand all the way to the river, calling every bet, you WOULD WIN more often than any other player! This is because you'd win those Q-7 off-suit hands sometimes. You'd occasionally pull off a win with 7-2 off-suit, too! The only problem, (and I hope this is obvious), is you would lose TONS of money chasing all these wins.
One more point - Follow these hands you don't play through to the end. Quite often you'll be very glad you didn't play. Your 2-pair that you flopped with Q-7 far too often loses to someone with A-Q when an Ace hits the turn or river. Then you lose a TON of your stack!
If you held 9-4 off-suit, and you see 4-4-4 come off on the flop, just chuckle a little inside your head and be glad your not one of those people who chase the "once in a while" crazy flop like that.