Don't worry about karma in New Vegas, it's used a few times for flavor but Faction Relationship is much more important.
Obsidian would have scrapped that system and the game would be the same.
karma is not like a reputation system or anything like that, it's just that if you do bad shit you create some sort of aura around you that's noticeable but not necessarily gonna have a much bigger effect that shaping someone's first impressions of you (with a few exceptions)
Hm OK. I will try not to let it give me a complex. The other thing that happened was, right after the early ambush in the tutorial town I was cleaning up loot and saw that the saloon owner was dead with her leg blown off. Felt bad She was all happy that I fixed her radio, too.