I'm going to put this one on the GM: they need to find out what need the player has which they're not full-filling.

One easy example which makes this point is a player who likes the rules and understanding the limits of the rules, who is playing in a group of players who like to bend rules in favor of imaginative epic-ness. What Robin Laws would call a "Tactician."

Ex: 

> **Other-player:** My 2nd level Wizard casts a fireball, uses it as a rocket to propel themselves at the dragon and make a charge attack.

> **GM:**  That's so epic! Forget the dice roll! The charge rips right through the dragon's body, landing your wizard right next to the tied up princess.

> **Tactician:** I take a defensive stance and ready an action to fire my bow.

> **GM:**  Ok. Now the dragon attacks you both.

> **Other Player:** I swing my sword to cut a hole in the dragon's claw and then jump through at the last minute!"

> **Tactician:** My defensive stance gives me +2.

> **GM:**  Other player, you make it! Sorry Tact, your +2 doesn't cut it against the dragon.

This GM is turning an interested player into a Casual Gamer by ignoring that player's needs and interests. Eventually that player will feel what they do is futile, and soon they will turn into a Turtle/Roach.

Some might say that given the inconvenience (or losing a turn to a def stance and then getting hurt etc...) the player should eventually catch on and change their play style, but this kind of indifferent punishment ('cause that's what it is) isn't cool, and the GM shouldn't punish a player for their game style unless it is _disruptive_.

Don't be that GM.