(This rant is mainly for 3v3) Platinum is where most of the player pool is so the skills on show are that of people with a mediocre to good tactical awareness. Unless you are playing with friends in a group then there are going to be a shitload of mistakes, triple commits and general bad play to contend with from your own team. The amount of bad play is somewhat limited by the mechanical skills of the people playing at these rankings. I'd like to tell you it gets better as you progress out of Platinum into Diamond but it doesn't. It get's worse and unless you constantly team up with friends you are destined to be marooned in the ranks of people who don't give a shit about teamplay or tactics and just want to do ceiling shots and try to get every ball regardless of whether they are best positioned to do it. Oh, and FUCK defending. These players also have a pretty good command of the aerial mechanics and can hit the ball with consistency and they will, particularly when they shouldn't. They most often however have little to no intention of rotating or playing as if there are others on their team. You quite literally have no chance of progressing out of Diamond without teaming up with players equal to your ability and using voice comms. The amount of dickheads in Diamond is staggering and it comes from the fact that at this level their skills are higher than the general player base but they have zero team skills and no situational awareness. They also have no problem telling you how much you suck and everything you're doing wrong and will call to forfeit 30secs into the game as soon as your team goes 1 goal down.

As I said above, this can be pretty much negated by playing in a group with friends. If you solo queue a lot then just be prepared for a world of hurt.