JP here and started 1.5 year ago, but a quitting experience nonetheless. My almost quitting experience was around summer 2017, I was kind getting bored of all the faming, and I stopped for a day (broke my log in), logged in the other day, did a 10 roll expecting a minimum roll and got caster nero. Needless to say, nero motivated me to play more (its a new servant, afterall).

Second one was on Raikou's banner on a tower event on february 2018, I spent 500 quartz, got two spooks, np2 jack, np3 tamamo, got salty because 300 of those quartz were paid (I cant spend much, so two 80USD hurt a lot in my country) and I ended up not getting the featured servant. The pain of farming the valentines event att, having other games to play, the salt from not summoning raikou and missing that weeks missions were the reason to stop (I still have 3 quartz fragments that cant be used for anything from that week that will always remain). So I stopped for two weeks, what I missed was that I didnt finish valentines (I planned to get all the special servant craft essences, but now I only have a few, I hope to complete them next valentines), missed KnK rerun (I lost my last chance at shiki there, not that I needed an single target assassin, but still) and some login bonuses of some pharaos campaign att. I came back because I already invested a ton of resources on FGO and still had servants that I like playing with, so I returned for saber wars rerun. and since then Ive been playing daily.