I've seen many shy, quiet, unforthcoming people blossom into confident public speakers in an environment which is (hopefully) devoid of real world consequences to our behaviour.

The skills which one uses at a larp event in order to shout defiance at a dark lord in front of an army of five hundred can then be used to negotiate payrises.  Once you've conquered your nerves on the mock battlefield, the boardroom is surprisingly easy.

Anecdotally, I recently found myself the only person in my office prepared to put questions to our firm's senior partners when invited to ask things at a conference.  I was in a room filled with people who cross-examine for a living, but as the sole larper, I was the only one with the confidence to be the first to put my hand up and ask something.

I personally suspect that this is due to all the practice I have at shouting at people who are allowed to have my head cut off. 
After some of the simulations I've experienced while larping, the office can do nothing to frighten me...

Internet Redcap: Don't make me put the hat on