That is a completely normal reaction.
When I play games like "Mass Effect" or "The Witcher 2" and even "GTA IV", I tend to adapt the problem-solving style or interaction style of my protagonist.
* For example, after playing through ME2 in less than 4 days, I noticed that I behaved much more assertive and dominant in discussions and day-to-day interactions (don't over-interpret it). I was much quicker to take charge and responsibility when co-working with others and often automatically assumed leadership roles.
* Simlar things happened while I was playing through The Witcher 2: when having to make decisions in a group or delegating tasks, my agreeableness had significantly decreased and I used much more of "You do X, you do Y, if you don't agree, fapp off and I'll do it myself" attitudes.
* While playing GTAIV, my typical ways of making appointments (and even dates) changed slightly. Instead of calling a friend a couple of hours before, I called while driving to somewhere and just told them to be there in like 15 minutes. Works.
I believe that these are pretty straightforward effects of social learning; it has long been described that people treat virtual characters as real people and then hypothesized that most of social psychology that happens between two persons also applies between a person and media (--> Reeves: the media equation, media=people). Studies with robots and digital avatars do indeed show that the usual social psychological effects occur between people and avatars or robots, although they are usually weaker (and are mediated by the perceived humanlikeness and presence of a character).
The whole "effects-chain", from perception through cognition in brain, implicit effects like priming or social inhibition/facilitation to explicit self-reported attitudes and mentalizing: it doesn't really make a difference if interaction is real or virtual as soon as such interaction is processed in our brains. I'm currently writing a research proposal on a very similar topic and to me this is one of the most fascinating domains on which you can study social intelligence and cognition
