It interests me how trends come and go in the workplace. One of the most recent themes in personal development has been 'authenticity'. In other words, being true to your self so that others really 'get you'.
What has been discovered after a recent study at Greenwich University, London is that authenticity is less important in the workplace than was first thought. So go on, put that cheesy grin on for your bosses jokes, it doesn't matter really.... you can still be professional whilst not being entirely true to yourself. It will probably do you more good in the long run not to own up to hating their taste in jokes anyway!
It is of course far more important to be yourself when at home, with loved ones and friends. Be true to who you are as in those circumstances and you'll be loved for being genuinely you, not something you are trying to be.