Man, trying to level characters is such a grind compared to just doing a run on my DH. There's nothing to look forward to besides inching ever closer to 60 and Inferno, which is the only place where anything matters.
I don't bother picking up items except rares, which you don't get that many of without Nephalem Valor. Elites are just a chore since they're not going to drop anything. And even the rares I do pick up are worthless 99% of the time, since I twinked my characters out a bit from stuff I saved during my initial run with my DH (or found while leveling some of the higher characters.)
Wizard is highest at 51 or 52 now, and it's annoying to play without the mobility of my DH. Yeah, there's teleport, but the cooldown is forever compared to just popping off a couple vaults or tactical advantaged smoke screens. Barb is only 24 or so, and also annoying to play, though less so. Monk is lower than that, and I haven't even made a WD.
It's tiresome having to go through all the quest stuff, especially after having seen it countless times already. But I know I have to do it, even if I skip all the side stuff, since you have to beat the previous difficulty to advance.
And this is all so I can try and switch off my DH who I've become a bit frustrated with in that she's not the most efficient farmer compared to Barbs, Monks, or Wizards with a comparable level of gear due to the glass cannon aspect. Yeah you have defensive cooldowns, but no defensive passives or tankability outside Smoke Screen/Gloom and when those are down, you're toast.