I hear it all the time from coaches and especially from divers -- "The judging today was terrible!"
In most cases, I disagree, because as I hope you are aware, judging diving is subjective; it is purely the personal opinion of the person sitting in the judging chair. What they like or dislike might be radically different than what you like or dislike. What they think is a good dive or a bad dive might be radically different that what you think is a good dive or a bad dive.
Something to consider: if all (or most) of the judges score your dive(s) low -- chances are your dive was not quite as good as you thought it was. If most of the judges gave your dive a good score and one judge did not (because of cheating or just inexperience) -- that does NOT affect your score one bit as their low score gets dropped when the calculations are made.
The point I am trying to make is this: You cannot do something (or NOT do something) on your dive that would cause the judge (or judges) to give your dive a "BAD" score. You need to coach your divers in such a way (or if you are the diver) you need to make sure your dives are better than "bad" judging. You have nobody to blame but yourself if your dives go into the water with bent legs, flat feet, feet apart or a big splash. Don't forget about entering the water vertically either! Even the worst diving judge in the world knows that each or any of these things makes your dive look bad and thus scream out for "BAD" scores! Any coach worth their salt knows that the key to diving success (especially at the younger age groups) is fundamentals -- namely good form (legs straight, feet together, toes pointed) and vertical entry with little or no splash!
So the next time you compete (or your diver competes) in a meet and you are angry at the "BAD" judging -- take an (unbiased) look back on your dives to see if there were not some numerous and / or fundamental errors that might have caused all the judges to simultaneously score you low.