Hi Fabrizio,

if the people attending were all friends of yours then you wouldn't fear playing before as many of them there could be, so it may depend on your own feeling towards your fellowmen and your relation to people in their whole. If you assume the attending ones all mean to rate and judge you bad then you get stage fright.

Also if performing in group it depends on who you're playing with, because too many musicians mistake emulation for competition. Skills and repertoire don't make it all and you got to find the right people to play with. I once watched Marcus Miller being interviewed and it seems those we call 'killers' are actually the kindest and humblest guys on Earth, which beyond their skills could be what makes them so busy.