Well, I actually feel like I have triple personalities...
1. Work/school personality. I work in marketing for a large corporation, and it's a pretty rigid and kind of formulated existence. Driven by goals partially set by others, and in the interest of the shareholders or the grander interest.
2. Photography - where my photography glasses and brain are always engaged to soak up information or something I can learn from. What I learn benefits me, and there are no rules to how I think or explore. Party time!
3. Family personality - where I let the guard down, have fun, and let go of both my photography and work/school brain, and just focus on enjoying life (or being responsible with it).
I think it's normal for people to have this type of role play living at work and in school, while at home with family, or working our passions, we can let our personalities run more free to balance out the rigor at work.