The dream that I woke up from before that was more interesting, although I remember very little of it either. The setting was "zombie apocalypse". I was with one group of survivors and we were attacked by another group, whom we defeated. Then one of their surviving members, who'd sat out the fight, threatened us with a submachine gun. I got the gun away from him, and told him to leave. He started to go, then turned and came back, with this leering, smug look, saying, "I know you're not gonna shoot me," and obviously planning to grab the gun back. I fired a warning shot, but he kept coming. So I shot him, walking the bullets up his body. He looked so surprised as he died.
As I woke up I was thinking, "What a waste of bullets." I felt regret over his death, too, but also that I'd need those bullets later (zombie apocalypse! Where'm I gonna get replacements?) and I shouldn't have used so many on one guy who wasn't even a zombie.
The funny part about this dream is that you'd think "zombie apocalypse with other humans also threatening me" would be a nightmare, but nope. No strong emotional response caused by the dream, neither fear nor anger. I've been more upset by the "surprise! it's time for the final exam in the class you'd forgotten you registered for and didn't attend all semester" nightmare.