I hate doing things wrong; I also hate missing parts of the game I love. The Cataclysm-era revamp of classic WoW zones drives me absolutely claw-my-eyes-out crazy, not because I recoil from change but because they force me to level "wrong." Unless you turn off your XP or scrupulously avoid battlegrounds, dungeons and even gathering professions, you have no hope of seeing more than a handful of quest lines at best before any given area greens and then grays out. It's just not much fun to keep slogging away at killing baddies whose dangers are laughable at best simply in order to finish a story line before moving on to two or three more stories in the same, deadly dull gray zone.
So I don't. I run a few quests, ding, run a few more, ding again, and then check my quest log and dump anything that's green or gray. At that point, it's time to move on, if not to the other end of the zone (can you find where the bread crumb line will allow you to break in?) then to an entirely new territory altogether.
I know many of you don't care if content goes trivial before you reach it. You still run your zones in order, start to finish, like a long line of dusty World Book encyclopedias on the shelf at Half Price Books. You don't care if you've outleveled the content; you want to see the show. Other players pick and choose their favorite zones and quests, and still others simply slam their way through the levels via dungeons or battlegrounds. That's my latest strategy, hitting the BGs; the atmosphere is downright jocular at low levels, and I've found things stay relatively whiner-free until at least the 50s.
When you're leveling, do you prefer to adjust your path to encounter content as "correctly" at level as possible? Do you avoid the problem entirely by heading into dungeons or battlegrounds? Or do you simply leapfrog madly around the map and among the gameplay options, leveling as quickly as possible to get the whole thing over with?