I can relate to everything the OP says, except for the ToM-piece. Sometimes my lies have even been superfluous, but I guess theyre all social-related. I think I lie mostly in situations where I foresee, that the truth would be to heavy for people. Maybe it means that I dont expect people to be open enough to deal with my thoughts and emotions without becoming close to traumatized, because my thoughts and emotions dont fit to normality. If I tell the truth I risk to be accused for being too sensitive, over-reacting and so on, and people often give me the advice to stop thinking about >important< stuff. When I tell something, people can also think its sad and try to cheer me up, when its not sad at all AND SO ON. If I see that it is going to be a big effort to be honest about personal stuff I mostly just shut up.
Lying used to be a problem around 20, and I got away with it, but it led me into confusion about myself, and now Ive learned to be honest even though I know I leave many people with a question mark, because I dont bother explaining too much, just leaving them shocked with my views.
Sometimes my lies have been generated by other people when I have received a question about a compact story they believed about me, and I just had to answer yes or no. It was just easy to say yes or no to continue with something else, whereby I didnt really realize what they where asking before I answered, and then it got complicated to turn around, and so there are situations where people actually make up stories around me like that, and I have a feeling of guilt afterwards.
I think it used to happen because I was used to adapt and "catch the ball" from my surroundings, and so such spesific stories and the expectation of the person asking me the question drove me to "go with the flow", if that is even understandable.
Concerning making a reputation: My reputation is in your head, spooking around along with your own desire to make one for yourself. Just watch and learn while I dont care.