For me, for sure I know it's one of the worst methods around but it completely deflects all suspicion and no one asks "those" questions so I use it as a last resort. I basically act my way through it, acting as a happy person and consequently bottling up my emotions for that evening. I try to say things that most people have said already so that I remain in the shadows. Just merely acting happy will ensure that your expression and atmosphere that you give off aren't "out of the ordinary". For sure bottling up your emotions is no good, which is why I only use it in a pinch.

Good luck!