What was the forgers intentions for doing their forgeries?

I've been reading on some of the Apocrypha lately and a question arose. Why would people make forgeries of such important texts? I understand that the writers were trying to gain followers to their own theological views, but didn't they feel any remorse on creating false texts? If someone would spend so much time on forging a fake "Gospel according to X" or a fake "Acts", or the "Epistle of Pilate to Tiberius" (which is the one forgery that made this question to arise in my mind) then this person would take his faith seriously enough as to justify such an effort. But then again, how come this author doesn't worry about falsifying what Jesus really said, or what his contemporaries thought about Jesus? I'm really puzzled about this. Thanks to all of you for your replies and God bless you.