PSA, Don't play ranked if you ban these champions.
In recent I've seen several people ban champions on bases on "I have troubles" or "I can't win against" mentality. Some maybe, but most are not.
Those who should NOT ban.
Aatrox, Ahri, Akali, Alistar, Amumu, Anivia, Ashe, Aurelion Sol, Azir, Bard, blitzcrank, Brand, Braum, Caitlyn, Cassiopeia, Cho'Gath, Corki, Darius Diana, Dr. Mundo, Draven, Elise, Evelynn, Ezreal, Fiddlesticks, Firoa, Galio, Gangplank, Garen, Gnar, Gragas, Graves, Hecarim, Heimerdinger, Irelia, Ivern, Janna, Jarvan IV, Jax, Jayce, Jhin, Jinx, Kalista, Karma, Karthus, Kassadin, Kayle, Kha'Zix, Kindred, Kled, Kog'Maw, Lee Sin, Leona, Lissandra, Lucian, Lulu, Lux, Malphite, Malzahar, Maokai, Miss Fortune, Mordekaiser, Morgana, Nami, Nasus, Nautilus, Nidalee, Nocturne, Nunu, Olaf, Orianna, Panteon, Poppy, Quinn, Rammus, Rek'Sai, Renekton, Rengar, Rumble, Ryze, Sejuani, Shen, Shyana, Singed, Sion, Sivir, Skarner, Sona, Soraka, Swain, Syndra, Tahm Kench, Taliyah, Taric, Thresh, Tristana, Trundle, Twisted Fate, Twitch, Udyr, Urgot, Varus, Vyane, Veigar, Vel'Koz, Vi, Viktor, Vladimir, Volibear, Warwick, Wukong, Xearth, Xin Zhac, Yorkick, zac, Ziggs, Zilean, or Zyra.
Seriously if those named above give you hell, you shouldn't play ranked. Come 10 ban system, it will be bliss for those of us who understand who and shouldn't be banned...

or
you should not play ranked?
(which i do frequently), and i like got out of 2 games in a row with an enemy or allied
, or someone dodged after i saw a player on my team or the other team pick her, and i don't see a person on MY team pick intent her, and the important 100% ban champs like
mid, im going to ask for a
ban if