I might be coming at this from a different angle but I think it comes down to competition. Well, I don't have any scientific proofs per se (bleh) but I think we are generally hard-coded from our DNA to try/want to be the most attractive. It's only when you are well aware it's not a threat, you'd be able to lower your guard down.
Now, if we are talking about opposite sex, then that's a whole another type of conversation.
I am going to assume that you don't consider yourself to be exceptionally attractive. Correct me if I'm wrong.
So, with that assumption, if you were able to wake up tomorrow morning and be on par with a "Brad Pitt" lookalike, how do you think that your reaction to interacting with them would change? What about with the other group of people that you currently prefer to engage with? After thinking about that, would you still prefer that things remain as they are?
>Now, if we are talking about opposite sex, then that's a whole another type of conversation.
This matters too, of course, unless you don't plan to interact with them at all in a professional environment :)
Now, if we are talking about opposite sex, then that's a whole another type of conversation.