Poker is full of situations where "it depends", and many times, it depends on more than just the cards.
To give you a different type of example than MedisBLITZ's, let's say you're on the button and two people have limped in. Holdings like small or mid-pairs, small or mid-suited connectors, or Ax probably make up a sizable portion of their ranges, especially at the micro levels.
A hand like QJ can play pretty well here because a number of favorable scenarios can ensue, such as:
- you raise representing strength, and the limpers fold,
- you raise and iso one or both with position and initiative,
- compared to Ax, you have 2x the probability of flopping top pair,
- even if you miss, the flop will probably have at least one overcard to the small and mid-pairs as well as the suited connectors, plus you have position and initiative,
- if the flop has an A, there's still a decent chance you can get the Ax hand to fold depending on his style,
- you can flop some kind of draw yourself,
This list isn't all inclusive. The key point is that "play well" doesn't mean you'll have the best hand, but rather that it will remain playable in quite a few situations; i.e. you won't be limited to fit or fold.