The thing about league, its addicting to the brain, you want to consistently see yourself improve, even when you're not trying or "playing for fun" you're trying to better yourself.
If you stop playing others pass you by and you stop growing, you come back your rusty. Human nature is to want to keep improving.
I used to be a huge CoD Player, I'd dedicate playing with my squad for hours on end, for the goal of wanting to be better, one of the best. We'd play in tournaments online, we'd skrim, we won a lot of money (for playing a video game). We all grew older ( I'm about to be 28 and I started when I was 18) and they for the most part are my age or older so we all grew up and got families and real lives. We stopped playing around Black Ops 2/Ghost, we're all Facebook friends and we all get together to play Bo3 and now CoD4 Remastered every now and again, but it isn't the same, its more just nostalgic playing with your old friends. The game that started it all for us, but none of us are anywhere near the level we once where cause we stopped playing, it makes the game less fun to know you are or were better then your opponents but you've decayed to the level you were years ago and your skills just don't make it anymore.
Weird sernerio sure, but it paints a picture as to why people who take League seriously can't find a balance to life and League, you either give it your all or you don't.