Ok, so I spoke out of turn as when people have this issue its mostly due to it being ranked, I am sorry for assuming.
While you play normal draft matches, and you find someone you enjoy....or better yet is not just a complete dick, add them to your friends.
if they are in norms they will tell you it either warm up...or thats all they play.
Your welcome to add me, im an old asshole of a man, but i just try to keep having fun, its a game after all.
But since its not ranked related...
i seen someone else posted this, and i would suggest it for you....if normal games are getting you down, sounds like you just play to much league of legends to be honest with you....We all get to this point if you love league...But take a month or more of and dont ever touch league....When you come back if your first few games feel like that....Then be honest with yourself...even tho riot does not want to say it....but if your not having fun with the game....Quit! Im not saying this to be a dick...like OOHHH AHAHAHAHAHAHAHAHA you cant win uninstall.....not at all winning comes with practice. But if it simply does not bring you joy.....whats the point in playing at all? If you have another game you spend hours on and never once feel upset...Go play that!
Gaming is a hobby, unless you make a living off it,,,,enjoy it...If you make a living off of gaming.....What do you do for fun? just wondering!