1000-1400ish is where it will be the worst.
1200 is where you start. "All players start ranked play with an Elo of 1200 for their first 10 games at level 30"
This creates an obvious situation. 1000-1400 games will have the greatest likely hood to have players who do not match there proper elo. By 1800, unless someone is playing someone elses account, they will likely have a correct value. But at 1300, you may be facing a 1250 player, who is really a 2000 player, who just started ranked, or plays normal 90% of the time.
These games will be inherently unpredictable. It is entirely possible for you to get screwed in your first 10 games, with shitty matchmaking. and your first 10 games have a very high +/- attached to them. As you play more, the +/- goes down. if you lose 10 straight, you'll need to win 15 to get back to even. (not quite accurate numbers, but the system is correct.)
Bad plays at all levels. Shit happens, and sometime its just random players have wildly different instincts and playstyles, that don't blend together. Doesn't mean one or the other is bad or trolling. and also consider of course, the guys that play 10 matches a day, do not care about 1 or 2 games. So, you get the quitters, trolls, etc. While again, if you only play 1 or 2, each and every game means alot more to you.
But honestly, if you are below 1400, worry more about picking up your own game first. Or just play normal, so you can sit back and say fuck it, and keep the rage away.