The only time that I missed a shiny was in XY so far. I was chaining and I FINALLY (Read: I was busy with this for 2,5 hours) on a 40 chain. So I got super excited since it would be my first shiny in XY. Everything went fine .. until I selected my bike instead of the radar and broke my chain like that.
You had no idea how quick I turned off my DS after that happened, the salt was real lol
You had no idea how quick I turned off my DS after that happened, the salt was real lol