[Razael]

No because for one, quests reward lots of exp and grinding X amount of mobs will sometimes triple the amount of gained exp when finally completing the quest. (Most) short/easy quests don't reward much exp, but if you notice, (most) of the harder/longer quests will boost your experience bar alot! Besides, grinding X amount of mobs can be an easy and efficient way to make gold as well as level in the process.

But then again, I suppose you can just do all the short/easy ones instead and make up the time that would have been spent on the longer ones. I rather enjoy the longer and harder quests regardless of how boring and tedious they can be, they usually pay off in the long run IMO.