If you are requesting people to add you please check the game to add people daily! This game loves to crash when doing anything that involves friends, and I think one of the reasons is because of so many friend requests waiting.
Bring up the game menu(the gear at the bottom, touch 'my friends', then touch the tab for the little person with the plus sign, wait for requests to show and accept them all. You may have better success accepting and waiting for them one at a time. And if you have a stuck person on the list, that's already your friend in the game, don't click to accept them again.