The reason I wanted to add that caveat is because I quite like being fake. It's 100% necessary. I can hate my boss all I like, but I'm sure as hell gonna be nice to him/her until I can change jobs, or, better yet, somehow get around them/get them kicked out/get promoted, etc. Or if I'm a reporter, I can think Joe-Schmo is a dumbass, but if I need him as a source for my story, I'm going to cajole him and be as kind as possible.
Especially for betas (but definitely for alphas too) "fakeness" is an essential tool in achieving one's goals. An SLE can learn to be quite socially adroit and polite and avoid offending people (although the radar will never quite be perfect, but ya know, Fe-HA; if you keep avoiding things that weaken the emotional atmosphere, eventually you'll manage to at least avoid offending the wrong people), as can any other type, if it suits their goals.
I know that personally, I see people that I'm close to as deserving to actually see me, good parts and bad. It means I trust them. I feel like the other people, who I'm not my real self with, I'm manipulating or deceiving in some way, and while I'm comfortable with that for people I don't really care about/trust/love, I would hate above all to feel like I was being dishonest with the people I care about most.