10 GOLDEN RULES FOR HOGWARTS GHOSTS
1. For reasons known only to yourself, you decided to float around a High School for the rest of eternity. This questionable decision has left you with free access to the next magical generation and a wealth of knowledge at your disposal in the form of the library and various intellectuals scattered about the place. Rather than take advantage this potential, either to sway future generations or to become an invaluable source of advise and information, you should float about looking sullen, crying at random intervals, and listening to acne-ridden morons complain about their Mean Old Teachers.
2. Begrudge the living. They clearly deserve for having the cheek to exist and, Lord knows, it's not as though you were given a shot at life or anything. Certainly not as though you all messed it up royally either.
3. Pontificate. Even though you've spent the past millennia moping, and even though you were probably a pretty messed up human being to begin with, you know everything. Because age is the only factor in wisdom, obviously.
4. If you had a doomed love affair in life, be sure to cling to it desperately in death. Some will say it's pathetic and a waste of time, but truly well adjusted people will tell you that it's romantic to stalk women for centuries even when they want nothing to do with you.
5. Act as though you all have some sort of jurisdiction over Peeves, even though he only listens to one of you. Choose to believe that the poltergeist listening to one specific ghost is a sign that all ghosts have more power over him than the living, rather than the more obvious conclusion: That the individual in question is scary as hell.
6. If, for some reason, you find yourself not feeling whiny and melancholy for any period of time, you should seek to fill this gap in your schedule with idiotic pastimes such as "Headless Hunts" and flooding bathrooms. There's probably nothing productive you could be doing with your time anyway, so why bother trying?
7. Creepily suggest that various students may one day "join you" in your haunting. While this is pretty effective at unnerving young male students when a certain leery bathroom dweller does so, it appears to be even more effective when formerly-middle-aged male ghosts suggest it to young female students, while also implying that they "Know" the student in question "Better than they could ever imagine". After all, most teenaged girls don't feel awkward enough as is, so adding that extra factor of the possibility of Undead Peeping Toms is great for making sure they don't get too confident.
8. If, by chance, you happen to know the current location of a long-lost, legendary artefact that is said to imbue the wearer with great intelligence, you should keep it to yourself for a thousand years or so. Just wait until an evil super-genius pops up and acts charming, then tell him. After all, he could have no possible ulterior motive or sinister intentions, and clearly needs to be made smarter. Besides, nobody could have possibly benefited from this knowledge earlier, as everyone knows that there's a surplus of intelligence around here.
9. If we agree to attend your stupid Death-Day party, the least you could do is ask the House Elves to provide some edible food, while directing us towards the non-crazy attendees. It's only bloody polite.
10. You died. This experience is one that will eventually be shared by every single person on Earth. Dying does not make you special. The only thing that makes you even vaguely different from the rest of us is that you are here to complain about it, a fact which garners you very little sympathy. Though it should be pointed out that what little sympathy you did will evaporate the moment you use the phrase "Just wait till it happens to you!"