You can have more than 500 of a stat by maxing your stat and then pick-up an ability with +x on this stat. And if you have more than 500 agility, your energy stays at 0 and you can't attack.
Also, I can do twice the summer cup/year and I can't do the spring cup.
 "Monster Arena"){kind=icon}
 "THE GAME OF SAVE AND LOAD"){kind=icon}
 "You must save your dog"){kind=icon}