I was in the 1000s for a long time while I was playing WoW, playing a few games of LoL per week at best, not caring much about my elo. Around 6 months ago I quit WoW and the only game I played was league, got up to the 1200s.
When they announced the rewards for season 3 I decided I wanted to try and get gold. One month later (33 days iirc) I was 1519 elo. Having achieved my goal, I lost focus/motivation/whatever and dropped to 1263 elo in just over a month.
Then I realised that the soft reset for season 3 would be based off your current rating and not your highest rating. In order to reach my new goal (Plat in season 3) I had to get my rating as high as possible before the season 2 end in order to have that small edge when the reset goes through. So here I am 12 days later, back at 1519 rating.
PS I didn't play much for that +250 I think I lost only 2-4 games