The aim always has to be to mix it with the best. If you're aiming below that, you're automatically underachieving by definition.
Yes, we probably can't win the league, but if we don't start every season with that goal then something is very, very wrong.
Similarly, if we qualified for the Champions League, we probably wouldn't win it, but the aim to qualify should always be first and foremost ahead of a secondary competition. And then when you're in it, the aim should be to win it.
So for that reason, until this season, finishing 4th always took priority over winning the Europa League. Now that the EL has CL qualification attached, it has more importance, but only equal to the aim of finishing 4th.