In Fallout 3, I got to Tenpenny Tower and spoke with Tenpenny himself, who asked me to go kill a Ghoul and get a key from him and said he'd pay me for it, and I agreed to do it. Then when I went to the Ghoul, I let him convince me to let him live and he gave me the key, which I took to Tenpenny, and I told him I killed the Ghoul like I was told to do.
Then instead of just handing the key over, I demanded more money than was originally agreed upon, and when he handed over the payment, I went into V.A.T.S while standing right in front of him, and disintegrated his head with a point blank rifle shot, looted his corpse for the key and more money, and threw the body off the balcony outside the tower.
It means I basically lied to an old man and extorted money out of him, then double crossed and killed the guy, looted his corpse and disposed of the body, and nobody even knows I did it.
Got to admit though, I feel kind of good about it, because it came off really quite smooth, and the old guy was kind of bad, to be honest. What I do feel bad about is completing a mission for the Slavers, where I had to capture someone and capture and put one of the collars on them, and this was after I helped fight against the Slavers at some point.
