This is a very serious question that needs a serious answer. When faced with an attacker, if you have trained in multiple arts, you should know which martial art is the appropriate response. I found a simple flow chart for figuring out if you should use jeet kun do, tae kwon do, bjj, etc. I hope you found this as helpful as I did.
In related news: I found an awesome new group on Facebook called “I F*cking Love BJJ” – they post memes and funny pictures. You should check them out.