If you have a disconnected, offsuit hand like Q6o, the chance to outflop an overpair is about 3.5%. Most of the time, that will be with two pair, against which the overpair will have about 25% equity since the board can pair. There should be no question that limp/calling with Q6o hoping to flop a monster is a losing gamble. The effective stack depth was only 40 bb. Sometimes these losing gambles work out. Don't let that upset you or suggest that maybe you should play trash, too. Just learn how to beat them on average, which means isolating them and value-betting, not cowering in fear that they might have gotten lucky.
Please don't waste your time and ours by posting every example of when someone's trash hits the flop. It happens. It's a normal part of poker.