Some one started a "What Misc items do you carry?" thread so I thought I'd start this one. As an example of what I'm talking about:
Even though the game is so bright at night I'll always find a camp and sleep til the next morning, even in hardcoe when this costs extra food and water. The only exception is if I'm staging an attack on a specific target where it would make sense to take advantage of the cover of night (ie the NCRCF).
I'll take the armor from dead bandits I find or kill but I'll leave regular people with their dignity instead of stripping them.
I'll only steal certain of the skill books after I've done a favor for the people who own them (ie healing the mole rat and fixing the generator in Sloan).
If I play a NCR trooper I'll only use military style weapons like the 9mm pistol and Service Rifle instead of any of the cowboy weapons.
If I get ambushed near Mick and Ralph's in New Vegas I'll lead the ambushers away before killing them so the kids playing on that street don't see it.
In New Vegas there's a scripted ambush where you get lured into an alley. I'll kill the ambushers and throw them in a dumpster then drag their previous victim out to the street where his body can be found for a proper burial.