But I've had the exact opposite experience. I've been more fun on this then other modes because; everybody plays to have fun, (Builds like Trickster's Glass Blitzcrank) jokes around, and doesn't care about who plays what. So, is this the more common experience and the people who have those just don't talk about it, or is it really toxic?
Probably has a lot to do with your normal elo.
Play a lot of ranked and just came for the game mode? You're with a mixture of try-hards and have-funs and that's a recipe for disaster. I've had 1 game (over 3 queues with dodges) where people were instantly calling roles and argued over stuff and were quite toxic overall.
Play mostly normals and have a high normal elo? You're probably only with players who are actually playing to win but not at the expense of having fun. The remaining ~18 of my games have been pretty awesome. My first game today we had a dc'd blitzcrank support for the first 15min or so and we still won in 21min without a surrender and just dominated and no one even complained when he finally connected. A lot of these games have had exceptional people with great attitudes playing, and I think it's mostly because the game mode is fresh and exciting if you let it be.
I said half-and-half. Usually the people that rage don't consider the fact that it's not just the people that play normals in this mode (ex: expecting anyone to be able to jungle well, despite the fact that some of us mainly play bots and ARAM outside of the event modes).
But, there's some fun ones, too. And I think the toxicity goes a long way for game enjoyment and even performance. I played support Lux back-to-back. The first one didn't go as well, but our jungle Kayle kept talking about how Lux was a low-tier support and shouldn't be picked, despite the fact that s/he wasn't spending any krakens. Then, the next game, my Graves ADC loved me, and I was able to push like crazy. We ended up losing a late-game teamfight with minute-long death times that let them turn the tables. We lost, but it was a really close game (we had the lead up to that point), and it was really fun despite the loss.
As for myself, I just want to KNOW that you're not playing seriously. For the most part, I want to get my wins for my icon. But, if you tell me you're just gonna joke around, I get in the mindset and just play around, too.
It's been pretty brutal. I tend to keep to myself, however many people are just there to troll with their pre-mades in my experience.
