Beginning players will often contribute to pots by limping (straight calling a bet) into hands just to play them, or "just to see" You are better off deciding whether your hand and position warrant a raise. If not , strongly consider folding and waiting for the next hand. You may hit a good flop after limping, but if three or more other players do, to , odds or you won't have the best hand.
When you dump J-2 offsuit and the flop is J-J-2, you might kick yourself for not being in the pot with your boat and the chance for a big payoff. But more often than not,a J-2 call will result in a quick fold to a stronger hand and a wasted cotribution to the pot. Even in late position, hands such as A-3 offsuit and K-5 suited are not strong plays. Sure, the flop might bring 2-4-5 or three of your suit, but the odds are definitely against it. Of course, an Ace is great to have in the hole as a strong kicker, but it is weak if the flop does not yield a second Ace.
