Whenever teammates do picks that are not strictly the meta or just do picks that I think are bad, I get extremely tilted. I started playing LoL a while ago, and I still somewhat adhere to the bruiser top, bruiser jg, assassin/mage mid, marksman adc, and tank/healer support meta. For example, I get really angry when I see stuff like Lux support or Master Yi top. Is this kind of mentality right, and if not, how can I avoid it?
How to not tilt?
Stay upright. HAUHAHUH ahem
Just because someone goes an APC instead of an ADC bot lane doesn't mean it won't work
Just because someone goes 
jungle doesn't mean it won't work. (It actually does work, really good actually.) If they lose lane or jungle or whatever, that won't mean that the champion they used is just bad there, it means the opponent had more skill (unless they went like 
top lane with 
)
The first thing that you need to realize is that it really isn't worth it. Some picks aren't great, but almost every champion has potential to be good with a player who knows what they're doing. Also, you can ask them to play something to improve your team comp. For example, you can ask your top laner to play a tank if you don't have have one and they want to play Riven or something. They can choose to listen to you, or not to. The big thing that you need to accept, though, is that it's not worth it to let your teammate's pick make you play worse just because you don't like it. You aren't them, you don't control them. Play as well as you can, no matter what they do, because it isn't worth letting their pick affect you like that. In the end, it's YOU who lost that game, not your teammate, because you didn't play as well. Sure, their pick is what caused you to tilt and not play as well, but in the end it's your fault you let it get to you like that.
In the words of the late and great Al Davis the best way to not tilt is to "Just Win Baby"
All i can think of is "why would anyone tilt?", when people make completely meta picks like lux support?
Yi top is just noobs, at that ELO it wont matter. Just get some control over yourself and stop being SRSBSNS.
just dont care...
[zombie-brand-mindblown]
You need to realize that you are extremely bad. Once you realize and accept that, what's the problem in your teammates being slightly more bad? Being bad and slightly more bad is the same thing.
