Agreeing with Mutant. It really is chilling to think that Gaeta would have drawn those pictures knowing he's just that invisible, and that useless to the Cylons that there's a fair chance they'd just get rid of him because of those pictures (Baltar, after all, could draw pictures all he wants. And you automatically contrast Felix and Baltar if you read this, since it's a story from Baltar's POV but about Felix). The fact that he really never was caught must have fucked him up so much. Add to that the fact that he must have known on some subconscious level, or at least on a subconscious level of concern, that the Eight was using him to kill people on top of that. If there ever was anything that would give you PTSD.

I certainly agree that that's why he was shown drawing pictures, too, as a way of showing how invisible he was.