You're going to lose about 50% of your games

If you're well matched then you should expect to lose about 50% of your games on average. If you can't lose without being an asshole then don't play.

It's never justified

Have you ever had a bad game? So then why do you assume the bottom fragger is "boosted"? Sometimes they are but mostly they are just having a shitty game. It happens.

Have you ever popped off and dropped 30? So then why do you think the Neon on the other team is smurfing? Haven't you had smurf-like games before? They are probably just having a good game.

It won't help anyway and will probably make it worse

Even if your team mate makes a very obvious mistake, flaming them for it will pretty much never help. They won't learn and they are just more likely to tilt and hate you which will make them play worse. You are throwing games every time you flame your team mates.

Being positive is better for your mental health

Try to be as positive as you can and you'll feel better, win or lose. You're going to lose a lot of games so it doesn't make sense to make the experience suck for you every time you lose. Just be nice.

It's a game.

Grow up.