This isn't your usual "DON'T TAKE NEW CHAMPS INTO RANKED" ranting.
This is a little PSA, a bit of advice. Regardless of whether you're a veteran or a newbie. Before you go head-first into Ranked, after a new champ has rolled out, learn how that champion works. Whether you got to fight with it, as it, or against it. It makes so many headaches go away.
No one says you need to learn and master every champ to be a pro, but you should have a basic understanding of how each champion works, even if you don't play as them. Cause good chance, you'll be playing WITH THEM.
The recent release of Yuumi, is Kalista headaches 2.0.
You got people who don't know their ass from their elbow, but its worse when they don't know a single mechanic of your champion. You try and engage, they're running off. It be the equivalent of being a Mega Gnar or Malphite about to Ulti a sure kill, 1 ULTI, 5 VICTIMS! Your teammate(s) high tail it, cause they never seen your champion, and don't realize you're opening up a world of hurt, a 5 second death knell, as the enemy team is unable to do a thing. THey're all knocked-up/Stunned. But... your ally ran off, you die and they go "Sorry, I don't know how your champion works" ~sigh~