The "rules" are not set in any order (not importance or anything)

1. When someone charges at you with melee pull out your melee wep, don't use guns (exept spies, thanks to King Wiley for pointing that out). "What when demoknight charges at me?" You might ask, well answer is simple: Pull melee wep and show that you have some balls.

2. When someone doesn't shoot at you (I mean close-mid range) even when you shoot he might be friendly. Walk to him and when he still won't start attacking you he is friendly. Ignore him or stay with him and be friendly too. If he "backstabs" you (was just pretenting to be friendly) then he is just an ♥♥♥♥♥♥♥. (love censor look btw.)

3. Let heavy enjoy his sandvich. He should appriciate that and if he won't, tauntkill him next time.

4. There is a button called mute, if someone annoys you on mic use it. Don't be like: "Mute him!!!!!!!1"

5. Don't level up stranges (I mean kill idlers to get higher level of strange) because that is just pitiful.

6. Don't send trade requests to people that didn't say they want to trade something.

7. As medic don't heal only one teammate, heal everyone.

8. If you have lost just tiny bit of HP, try to look for other players coming to medikit that are in bigger need. When you will pick up medikit having a lot of HP and then see someone that needed it more than you, apologise.

9. Give sandviches to medics, just a reminder.

10. If you don't know for example russian, don't go to serv with this language. You won't understand anything and might end up kicked from serv from reason unknown to you.

11. Let people enjoy their taunts

12. Extinguish teammates (Using airblast/jarate/mad milk)

13. There is a thing called chat. You can communicate and stuff.

Well that's all but I'm open for suggestions. Please inform me about typos I made.
I might also add some screenshots later.