Here's a top 10 I learned when dabbling in airsoft with a bunch of paintball buddies...
1) It doesn't hurt. The people that think it hurts don't play paintball.
2) The first thing you do is paint over the orange on the barrel.
3) Cops don't like #2. It gets you handcuffed, on the hood, while they search your car. Three times on the way home. After they're done embaressing you, they play with your airsoft gun.
4) With some upgrades to the gearbox, you can easily hit 450+ fps. People will cry though. The same people will laugh when your gears, piston, & springs explode out the side of your gun because you cheaped out and didn't get the reinforced gearbox.
5) Spec Ops helmets may make you feel "tactical"... but us jihadist players will refer to you as "Spec Eds" for the rest of your life.
6) M4s will break in half if you land on them. AKs & AUGs won't... usually.
7) Sling your grenade and/or nerf football rpg launcher correctly, or you'll get a concussion when you trip at a full run and it smashes into the back of your head.
8) The police at the hospital don't like it when your carried in, with everybody dressed in full assault gear.
9) Appearently it's uncool to throw paint grenades at people in an airsoft event.
10) Don't ask me to surrender if I'm still shooting at you. That's just silly.