Some Simple Truths about League and how this works:
I have been here since there were only 40 champions. I take the occasional break, sometimes weeks and months at a time, however beyond that I have seen every single champion be released (or popped in soon after.). I remember Phreak being a player with a big mouth. I remember Season 1 and all it's hype before it started. I have seen the creation and removal of countless items. I have all of the Legendary Skins, I have at -least- one to two skins for every champion (save the three champions I sold back), and I have spent roughly 11,000$ on this game. NONE of these things are said to boost my ego, as my ego is fine, nor are they to impress. They are merely stated as credentials for the list I am about to post. Let's begin:
Stop asking for True Damage. I've seen numerous posts recommending items that bear True Damage, and if you think that Sated Devourer on Yi is bad, you missed a few things in the past. There is a reason that only two champions (until Vayne and then it was three) could use True Damage. I think that RIOT has forgotten this, but your asking for more is not going to help. You cancel all armor, health, MR, etc. This is why, during RIOT asking players for Tower Rework ideas, True Damage was denied.
Champions Are Released Broken (Except Vladimir, he was the only UP champion release I've ever seen, but that is still broken). This is a fact of business and will not change. Incidentally, it was much worse. For those that missed it, Garen would kill you at half health, and all he required to do this was to spin on you (thus Spin to Win). This is not new.
Items are Not the Problem. There is the occasional item that is just game breakingly terrible in their math (or their failure to account for certain champions, like Malady was or Devourer is.). That being said, the rest of the items are fine. Atma's existed for a very very long time before it began to be used on nearly every AD Champion. The META changes, based on what is currently seen as the 'best way to play,' and because of this items will be overused or underused.
Normal Matches are Normal. Ranked is Separate. Many people get upset when others take Normal Matches seriously. Others get upset when they are NOT taken seriously. They are the normal state of League of Legends. It was simply how the game was, and thus named Normal. The rules involve what you can and can't say, and whether or not you can just launch yourself at the enemy team. While there are others, that is basically it. People can play how they wish, build what they wish, and fail if they wish. That being said, when joining a Normal Match with the intention of failure... you should be removed. There are bot games for that.
The Meta is A Fad. I have seen so many 'Metas' that it is blatantly obvious to anyone paying attention that this is no more than a fad. The Metagame changes so extremely often that it is near impossible for any such construct to exist for long term in any given state. Thus the argument of 'Breaking the Meta' or 'Following the Meta' are both rendered meaningless arguments. The Meta changes, this means that it is broken at one time or another, whether by playstyle, champion release, or item release. Therefore exploding about one or the other concept of the Meta is moot.
Players Will Troll. Unless RIOT becomes so iron fisted that they will remove players permanently from the game for annoying someone else, and you have to play by not chatting and always conforming to what you see in tournaments without deviation? There will be trolls. We all know this, but few like to consider how strict the rules would have to get to rid the game of them. Report/Block them and just don't deal with them again.
You Aren't A Professional (obvious exceptions of course). If you aren't in a professional team, and you don't get paid in some way to play this game (the very definition of professional... though this can even include your streams.)? You are not a professional player. When you quote to others that 'well, so and so says this is how you play suchandsuch' you are setting yourself up to either become stagnant in skills, or long term failure. Singed was a tournament winning key in Season 1, played as an AP Bruiser that spam laughed. Where is he? See the flaw?
I'll come up with more later.