I've experienced 'playing the rules' on more than once, but one that still sticks in my mind occurred at a local gaming club four or five years back.
My local gaming group decided to attend an open event by this club, and took along WH40K armies.
My first opponent played Necron and had memorised every single rule, incorrectly, and every single errata, incorrectly. A thoroughly unenjoyable game as this lad interpreted all the rules to his benefit and wiped me out.
Second opponent was worse – playing Tau, he proceeded to carefully arrange his army on the start line. As I was playing Imperial Guard I was preoccupied with my own considerable set-up so didn't notice what he was doing until his first turn.
He moved his first unit, and meticulously measured out 2" gap between all the troops – so as to negate the worst effects of blast weapons.
My heart sank as he repeated this for his second unit and by the end of the third squad's movement, he'd spent nearly fifteen minutes moving 30 toy soldiers.
I quit there and then. Life's too short to be involved in things like that.