I do put myself into characters a lot of the time. But lately, I've been working on creating character profiles of detailed characters (they aren't necessarily in my story, but are just random characters) that AREN'T mirror images of me. However, in my stories, my protagonists are usually very similar to me, or my ideal self. Nearly all of my protagonists are young females (usually in their teens, though my current story is about a female, in her late twenties), who are shy but talented in a chosen career/subject. They have one or two of my hobbies, they usually have my tastes in food, and did well in school. Their personalities are far more varied, however... It gets very complicated. lol
I wouldn't say that I place many of my characteristics into my protagonist, however, I take traits from people I meet, know, see, etcetera and then take them and place them into the characters that fill my protagonist's world. I must admit, however, that one of my supporting characters is more like me than the others, mainly because he was the most difficult to flesh out, so I took him and gave him some of my traits, which then branched off, he is more of an extreme version of myself in some aspects. I find it very difficult not to place a piece of yourself into each character, or at least, a projection of who/what you want to be. If you take traits from people you see/know it makes them more believable because people will notice them and say "I know someone that does that!".
I guess you are the only person you know through and through, so to create a character who seems real through and through, a little bit of you finds its way in, intentionally or not.
