Reports will probably never be taken seriously 90% of the time.
People that flame, feed etc. Don't care that they are getting reported because riot won't do anything about it. In a normal game I played my first game of tryndamere, and for the first time ever, an ENTIRE team flamed me (little did i know that they were clanned up) Anyways, it literally made me want to afk. I took a minute to just breathe and calm down and focus on objectives. Because I felt like despite not being strong kill wise, split pushing was strong enough. But of course i died at top inhib and they flamed again. BTW we had a first time rengar who literally died more and did less, but because they were clanned up, they didnt say anything about it. We ended up winning, and i reported all of them for being absolutely toxic, like the seriously awful things you just shouldnt ever say/type. I know though, my reports wont be taken seriously and it just startles me how nobody even cares.