The only reason to show your cards is if you want to 'tell a story'.
For example, if you want to convince people that you only bet when you have the nuts, then show when you do. If you are lucky and they believe you you can sometimes get away with bluffs with a largish bet. If they believe your 'story', that is. If you have bad timing, as I generally do, you'll pick the one time your opponent has AA and hits their set and all that work goes down the drain.
On the other hand, if you are a TAG or NIT and you get away with an outrageous bluff, showing will make them think you are a bluffer and, again if you are lucky, when you do have the nuts they are likely to donate their stack to you.
In MTTs, the early stages anyway, either you get moved to a new table or lots of new players get moved to yours fairly frequently so there is little chance to reinforce your 'story' so don't bother showing.
In Micro S'n'Gs people tend to get knocked out reasonably quickly, so once again it's not worth showing.
I guess that in Cash Games or the later stages of MTTs it might be worth a try but in those your general play tells it's own 'story'.
All in all probably not worth it unless you are a future Hall of Famer.