Fans running onto the field is never a good idea.  If you ever do make the choice to be "that guy" who runs onto the field make sure you keep your wits.  Running out looking dumbfounded and barely moving will only get you a mouth full of grass and blood.  Just watch what happens to this guy when he tries to "soak up the moment".

Running onto any field of play has it's good and bad points.  The good last for only a few seconds and the bad almost always end with a concussion.  Check out some of the best field crashers around, including some who decide not to wear clothes.