I know I get trolled a lot by going on a 10 game winning streak easily carrying games, then get promoted and get a streak of 3 dumpster teams that are unworkable.
Not much you can do, but its retarded that you have to spend another 6-7 games (3-4 for another series and 2-3 for the promotion) to make up for it.
On another note, its not a static number of games that cause a demotion, and some games where you get dumpster teams the elo system is accounting for that so you'll get a lot of lp if you somehow pull it out and won't lose anything if you lose. Somehow I've gone on a 6 game losing streak without getting demoted (don't ask!)