In addition to what Stephen quoted me as saying (nice to get noticed!), i'll add this too. It depends on the die used, a sorcerer in my campaign rolls d4's to determine the damage of his magic missiles and regularly rolls 1's, in fact i'd go so far as to say 80% of the time. But he is notorious for poor rolls and we just put it down to a curse of some description by a disgruntled gypsy woman... Where-as I, the all powerful GM, once spent an entire evening rolling nothing higher than a 6 on a d20 for my monsters attacks... it was not a good night and i truly wondered at the 'random' element myself. However all rolling is just probability and since each side has an equal change of being chosen (even more so than real life where dice can be damaged/weighted to effect their outcome...) i just had to shrug and call it a bad night. If truly in doubt, head to a test campaign and type /r 999d20 (or whatever die you were using). Strap in and wait for the results, if they are 80% ones then i'd say the gypsy woman has cursed you also ;)