bronze: you legit don't even know how to play the game if you are stuck in bronze and trying to get out. You know nothing of match ups, build pathing, rotations, you are quite literally illiterate in the game that is league of legends. You yourself most likely hate the game, if you are bronze for you just legit don't even know how to play the game.
Silver: Congrats you finnally know how to play league of legends to a good enough level where you can actually have fun. You know basic itemization, you are familiar with the match ups you practiced and the idea of team comps and objectives are starting to enter your mind. However when it comes to thinking about the big picture of league of legends you struggle with, and if your team loses lane phase, you will most likely not make a come back for you don't know how. You as a player are most likely very limited on stratagies to the point most silver games go down to what I call. "araming" where both teams just run it down mid a million times untill one team finally wins a full committed fight so they can charge the enemy nexus or take baron.
Gold: Congrats, you finally don't suck at this game. You are one of the better players, you can brag to your bronze and silver friends, but when you look at the better players such as plat diamonds and so on you know you still have a lot of learning to do. You are familiar with most match ups, you know a large varity of build paths, and you know about rotations. However when you attempt to do the more complicated strategies on league or do some hard mechanical combo it's normally sloppy. You understand deeper concepts, you can do it, but once again the form and technique is just not their yet. Your sloppy.
Plat: Congrats you are actually pretty fucking good at league now. If you are a true legit plat who didn't get boosted, you can easily dominate gold, silver and bronzies to the point it looks like a cruel joke. You are very efficent with your main roster of champions and finnaly found a role and a champion pool that really clicks to you. Your rotations are pretty clean and when you are in a match up you are comfortable with you tend to dominate it. Your greatest flaw at this point is while you are good at league of legends, at this point the only way you will grow in elo is if you nail down the small little details. Understanding how to read the map and any info your wards give you. Learning how to predict what the enemy wants to do. At this point you are playing with some of the best players in the world, so the only way to grow is to iron out the small details that low elo players aren't even aware of.
Diamond: Congrats you are legit at this point one of the best players in the world. You are a beast, a monster, you walk into a league club and steal some poor bronzies girl friend going as you whisper seductively into her ear. "Diamond division 3". You send shivers down her spine and before the poor guy knows it, your walking out the club with his girl. If you are given your main, it's a free win, your rotations are fierce and constant to the point you forget what even is lane phase. My personal critic against diamonds, is many diamond players lose the ferocity that got them to diamond. They are afraid of demoting and start playing very safe champions and use very safe strategies. They forget the only reason they got diamond was by being a fierce player who took risks and made them work. Many people are stuck in diamond purely because they are prone to horrible tilting (see red mercy) or to afraid to take calculate risk vs reward plays (once again see red mercy) A diamonds worse enemy is his fear of losing and getting demoted.
Master/Challenger: I don't even need to say anything at this point, your so good at the game to the point major companies are willing to give you 6 digit contracts in north america just to represent their brand.