If you have a string of bad luck that drops your rank far enough you can get stuck in Hell. A rank so low that all of your teammates and opponents will be crayon eating morons or people trolling. Then it will be entirely luck which team gets the least idiots to win, making it take forever to boost your rank back up.
LOL, I was gonna post almost the same thing, but was going to call it purgatory. The strange thing about the rankings is that after awhile, it's hard to trust them. When my team of 3 queues as 4v4, we sometimes get people with a ranking of 100 that seem borderline retarded, and sometimes get people with rankings in the 500 to 1000 range that play fine. I think we lost to you and Suora a couple days ago so you're another one that dashed my dreams of mediocrity.