Everything I need to know, I learned from D&D

[Cerebral Paladin]

Rope saves lives. (Okay, so it's not very applicable in lots of urban living situations, but if you go camping or something... )

 

[fba827]

Killing things makes you a more advanced person.

Your friends will betray you if a special item or money is involved

Sometimes, the little details don't matter; other times, they mean the difference between life and death.

 

[graywizard8]

Always carry a 10' pole.
When in doubt attack the darkness.

 

[Saracenus]

• Friends don't let friends use wands/rods of wonder.
• Its pronounced koo-day-grah, not coup-da-grace.
• Fireballs might be sexy, but a shaped gliterdust will make your DM cry.
• Killing a Kender (as a singleton, in small numbers, or even as a race) is not a crime. If the Kender in question is a PC, it is a mercy to the rest of the party.
• Never, ever, ever draw 1 to 4 cards from a Deck of Many Things, ever!
• Someone has to pay the stupid tax. If you help someone avoid paying it for their own actions it generally will be transferred to you instead.
• A goblin vampire is a great foil/villain for a DM to use against the party. On the other hand, if you are the on the player side of this, it sucks.
• Never let the drunk dwarven [insert class here] with CHA as a dump stat be the party face. Otherwise make sure your PC has soap-on-a-rope for the inevitable trip to the King/Prince/Duke/Baron's prison.
• Wishes are for suckers.
• Intelligent magic items sound like a great idea until you get one, then you will suddenly want to book passage on a ship so you can dump it overboard in the deepest ocean.
• There is a reason that most spells that allow you to travel to other planes are high level. If you DM lets you get there before you can cast one of these, its a trap.
• Why do you need a rogue to disarm traps if you have a Barbarian?
• When a "friend" of the DM shows up to play in one session of your ongoing campaign you will be betrayed.
• Paladins are a pain but you can mitigate that by getting them to violate their paladin code and then they are just annoying fighters.
• Remember to shake the halfling thief upside down when leaving the dungeon. Stuff seems to just fall into the most unlikely places on their person on "accident."

EDIT: Forgot to add...

• If the party wizard has to allow himself to be swallowed by the Advanced Fiendish T-Rex of Legend to save your PC by teleporting your stomach-acid melted body to safety while the rest of the party runs for their collective lives, yes you did something stupid and wrong... stop making excuses.

Just a few off the top of my head...

 

[TarionzCousin]

It is NEVER a good idea to have sex with the attractive female NPC.

Spoiler

It's a trap!

 

[pawsplay]

If you screw up in a big way and die, someone else with a completely different set of skills will have to come in and pick up your slack.

What's a little racist banter between friends?

If you recover stuff that's been stolen, nobody owns it. Except valuable artifacts. Someone is always looking for those.

"Professional adventurers" have a high degree of job security, except when people who hire them try to kill them.

Some people are less competent and capable than others. Their lives are less valuable than most people's, and their fate is to obey others, likely to their eventual doom.

Nothing is more deadly than a pun begging to be told.

 

[ourchair]

• Its pronounced koo-day-grah, not coup-da-grace.

• It's actually "koodegras," from the French for "blow of mercy."
  
  Koo-day-grah would mean "blow of fat," or "death by fat."
  
  Which is something that happens to players after eating too many pork rinds, funyuns and pizza slices.

 

[TarionzCousin]

.

Random encounters happen.

(Reported)

 

[Thagdal]

If it's in chains in a dungeon, its a polymorphed demon waiting to trap you.

If it's pretty, and in a dungeon, its a polymorphed demon waiting to trap you.

If it's pretty, and in chains; Run.

If you're 8th level, you get to learn how to cast spells.

You can find treasure in the sewers of a city that will be worth more than the added up income of everyone wholives there.

 

[Festivus]

I used to read D&D books with a dictionary nearby. At 12, I had no idea what dias, inverted ziggurrat, bailey, bas relief, etc meant, so I looked them all up.

Always tap the hallway ahead with your 10 foot pole too!