I have wondered about how career actors approach their personal lives. Where, and if, the acting ever stops, and if they themselves understand where that division is. Hell, the only thing I've got on my homepage is in complete contrast to that (ironically penned by a playwright.)
This is what actors think 24-7:
"All the world's a stage,
And all the men and women merely players:
They have their exits and their entrances;
And one man in his time plays many parts,..."
William Shakespeare - All the world's a stage (from As You Like It 2/7)
Truly, I believe that to really listen to and follow one's Muse, one has to be fairly crazy. The vision and energy required to produce a great performance, a serious piece of art, or a full-length novel requires a certain level of detachment from mundane reality, and a single-minded commitment to creation that can have all sorts of ugly side-effects: alcoholism, drug abuse, sexual perversion, crime, you name it. Look at the life story of any actor, author, artist, musician or (shudder!) dancer you admire, and you'll see the pattern.
The real troubles start, IMHO, when said Creative Person misinterprets their own abilities, and begins to apply this sort of approach to areas outside of the artistic realm. The point about "celebrity activists" like Penn that has been made many times, is that they treat politics as just another role to adopt, or piece to create, and expect the same unquestioning adulation in that field that they're used to getting from fans. It's both comic and tragic to see someone like Barbra Streisand demand that her ignorant political spewings be taken on par with her stunning vocal performances, and then recoil in horror when the rabble have the temerity to talk back. "Shut Up and Sing," indeed...