Save/Reloading, aka "save scumming". And I'm perfectly happy with it.
I'm surprised no one has listed this one yet.
I will save/reload a game of Crusader Kings 2 10-20 times to make sure all my children have the 'Genius' trait, then I'll save/reload 10-20 times more to make sure they all have brilliant education events.
I'll save/reload to make sure I get the stealth XP bonus in Far Cry 3 for every flag.
I'll save/reload in Bethesda games to minimize stimpack/potion usage.
I'll save/reload in Bioware RPGs to minimize fixed-resource usage (medigel-which is XP!, potions, xp, etc).
I'll also save/reload before conversations so I can see all the options without having to replay the whole game.
Also:
grey_space said:
I'm a terrible min/maxer in RPGs.
I spent an hour rolling stats in Baldur's Gate Enhanced until I got the 'perfect' stats for my elven fighter mage. I kept leveling characters in Skrim and Fallout until I felt I had the right 'balance' (ie; OP) for endgame. it always makes any endgame confrontation an anticlimax for me but I just can't help myself.
Every single open-world game I play, I always max the levels out and discover every location/finish every side quest on the map before starting the main quests.