Oh, where can I start?
Character builds instead of actually created characters. Builds look to optimize character creation to its ultimate end. And not actually represent an actual person the player has put time and care into creating and conceiving.
A build is just optimized, mechanics. Without any meaning behind them. And I think that the type of player who lusts after builds just completely misses the point and fun of roleplaying games. They get absorbed in mechanical advantage. And forget the rest.
GAH! Players like that frustrate me no end! And they are a misery for a GM to have to deal with.
I'm an old Champions GM. And this problem has been one since the game's outset. Players who completely miss the fucking point of actually playing a superhero RPG in the first place.
Want to make me a happy GM? Make a character. Not just a mass of mechanics on a character sheet. With nothing backing it up! I need to know why your character is a hero, and what motivated them to put on a costume in the first place. I need psychological hooks to playoff. I need substance to help me actually craft adventures that have actual meaning to you, the player, and your character. Give me story elements to work with!
If you have spent any time at all actually reading superhero comics. You should get the pathos of them and be able to encapsulate that within the character you create. This is not a big request. This is actually part of the stated premise of the game. So get off your ass and actually CREATE!
The character sheet, the game mechanics are just tools to help in telling your character's story. They represent a mere fraction of the entire experience. They are not the main point of the roleplaying experience. And treating them like they are derails the experience for everybody else. So just fucking stop it!
If I posted this on TBP, I would be accused of being intolerant of other people's playstyles and likely get a warning or a ban. But no. My frustration comes from people who waste my time and only provide a character sheet. With nothing backing it up. People who do not finish the job of actually making a fully realized character with the necessary components for a GM to actually make it work.