What is the first you want in a server?

Im a about to open a minecraft network and keep wondering what should i focus on, I mean I know everything is important but whats the point of opening 10minigames if they are filled with bugs or without kits, or not enough information, buildings,etc

So, what do you think is the most important thing to focus on, whats the thing you really dislike about entering a server or whats the thing you cant live without in a server like not having survivalmode or creative world, maybe not having an specific plugin.

Would love to know you opinion.