The "little things" that you are a sucker for.

[Thamian]

A nice, subtle and understated sense of humour that's as dry as the Sahara. Case in point was certain of the technology descriptions in SMAC ('As this technology becomes more commonplace, boring repetitive jobs, such as product packaging or VP of Sales, will be done by robots'), or for a more recent example, similarly dry observations in Endless Space (such as rounding out a reasoning for why helium gas giants are hellish places to colonise by pointing out that atleast there is some entertainment to be had when the habitation modules lose atmospheric containment).

Others have commented on how well rounded/well built characters are this, but I'd call that a pretty major element of a game myself. But then I'd also call a good sound design a major element, and I bet most people never even think about that one, so what do I know?


P.S. Captcha: 'skynet watches'

Scary much?

 

[SoulSalmon]

Customization, especially of appearance.
I will feel almost forced to give a game a good hard chance if I look at the character creation screen and see something like this:

Things like the transmutation stones from Guild Wars 2 is a perfect system in my eyes (transfer the stats of any piece of equipment to the appearance of another). The Path of Exile skill tree is heavenly. Minecraft mods and texture packs are so vast and easy to obtain/use. Enchanted/upgraded weapons having glowing effects is awesome. Etc, etc, etc.

 

[bigfatcarp93]

A sense of hoplessness. NOTHING makes me want to keep playing like a good, crushing, sense of absolute hopelessness.

 

[feeback06]

Side quests that reward me with loot, and optional end game bosses. However one of the really big ones for me is an aesthetic change in my character's appearance. Don't get me wrong, that probably isn't a huge deal in games these days but go back and play an old dragon quest game. Your characters were in their default costumes 95% of the time or you didn't even see them. If I get a bad ass piece sword or piece of armor, I want to see my character actually wearing/wielding it.