Advice for those who complain about match making especially normal modes
Don't look up player ranks and stats until after the game: If you really care that much. Trust me it will save you headaches in the long run. I used to look almost every game especially back in my silver days and think/say shit like "o snap I am against a plat player I am fucked or yo Bob your against a diamond top good luck" etc. etc. That just tilts yourself and your friends. Instead of you just go into each game trying to think about your champion and the match up and the game you will do a lot better. If you have a good game or a bad game and think "o wow that person was really good" and want to check their stats then do it after the game.
Also, remember normal mode is not ranked. A lot of players don't play their main champs or roles always in ranked so even if they a higher rank than you they may be learning a champ or role too. Or who knows they could be trolling with friends or drunk/high etc. It's really not worth getting bent out of shape or at least super bent out of shape about match making in norms.
And I get it, it can be very frustrating especially when you trying to teach friends or just want to chill and have fun. Normal mmr and match making different than Ranked and a lot of players normal ranks (mmr) don't match their ranked. I am one for example, although it is getting closer. I have been playing since season 1 (and may finally hit plat this sesaon lul... haha) and used to play only normal games or mostly normal back in seasons like 1-3. I had literally like thousands of games played, which obviously gave Riot a good number of games to estimate my normal mmr. Well after that a lot of my friends stopped playing and I focused more on just ranked games so I haven't played as many normal games over the years as I used to. So a lot of times when I went into norms most the people in my games would be silver/bronze, which makes sense seeing that used to be my skill level and my win rate was rather low. But now I have been playing more normals and been winning more so my mmr been going up so now it more Plat-gold players, which matches my ranked mmr.
Unfortunately I think it takes a lot of normal games to get an accurate mmr. It seems new accounts start out with high mmr for norms and any Alt accounts I have I generally mostly only play like diamond/plat plaeyrs. But... not a lot of normal games played on them and I am sure they were labeled as "smurfs" since I would win most of my normal games to start.
But anyways I think f you just don't look at peoples ranks and just play the game instead plus just try to learn some things along the way not only will you have more fun game to game but you will also improve as well. Just my two cents.