Can do:
- roll an alt, second, third character. MMO's are designed for this. If you now have a barbarian, roll something different, lets say a Wizard or FvS, a 'blue bar' char. The same quest can be much different if you are barb or cleric.
- lowman, solo stuff. Things are much different if you are not in full, perfect party. More challanging.
- perfect your favor with different factions
- True Reincarnate. You keep all loot, but start from lvl 1 with bigger char.
- do Perma Death or something like that
It's the same with any MMO. All have limited 'default' content. To get more, you create your own content.
I'm alt-o-holic and multiclass-o-holic that likes to solo, lowman quests. I also like to collect Bloodstones. Don't need them, just like to collect