That Renekton player will flame you if he's aware you did this pick intentionally and smash him.
Extremely common ban amongst Renekton mains. The ability to negate Renekton's stun is extremely powerful, even if it's not as strong as Quinn E+Q denying Renekton any ability to do anything at all. Renekton is strong against mana-based poke, not auto-based poke like Teemo because he simply cannot walk up to his wave to Q sustain easily.
Skill-based matchup. Heavily determined by how many E's you can land and if you know how to guarantee Q's after W slow.
Need to know how to play him, but his laning craps on everyone.
Wins. vs bad Renektons, especially if the Renekton in question goes glass cannon.

Renekton can't duel either of them post-6 unless ahead. Olaf specifically can just run Renekton down with successive Q's if played correctly.
Ranged champs in general when played correctly crap all over Renekton, as long as they auto more than use abilities for lane pressure.
Lv2 Ignite cheese and you'll stay ahead most of the game vs. mostly everyone, Renekton included. No sustain so if you fail, you will likely lose your team the game.

Good in lane, might screw your composition over depending on what you do or build.