I have INCREDIBLY bad mmr xd
So I was like gold 2 2 weeks ago then i was like "oh shit, riot is just gonna rework evelynn so why play her in rank anymore???" So I decided I would learn shaco in rank xd. Long story short... I was at 50% win rate, now I dropped 30 net wins below even and get +12lp for wins and im playing with low-mid silver from where i was playing with low plat-high gold just a bit ago.
TL;DR Don't tilt and learn complex new champs in rank :) Learning shaco has been one of the most happy experiences of my life though. He is love. He is the best champ in my jungle pool now and i plan on learning maybe one or two more soon but not in rank this time :)