My Favorite RANDOM word would have to be "Damn", as it can be used in many different situations such as:
"I forgot my keys, Damn!"
"Hey dude, look at that fine lady by the counter, DAMN!!"
"I'm sorry you didn't get into our college...Damn...."
See! it can be used for anything, anywhere!..yu know except aroudn your parents or old people? Lol..