I only act when I'm literally recording lines from a script (which makes good voice practice and a chance to imagine other lives). It's too much trouble and energy to try to put on a fake persona when merely dealing with the social situation as-is already takes all my energy, and I don't have situations that motivate me to do so. It's much easier for me to subtract than add: I hide aspects of myself, I avoid revealing things that'd make me feel exposed, rather than projecting any fake things (which would seem to me to require an advanced stage of social fluency to maintain believably).
Of course, a lot of people have to act every day for their job. Customer service for example.