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Part of my strategy was just to play open mics as soon as I had 20% energy because a> I wanted to hit some of the battle achievements that give out card rewards and b> I'd often find some coffee or pizza or something that would help get the energy back up, and then I'd do the bigger missions. I might have to re-think that. Maybe the pizzas and stuff aren't as common the further along you get into the game.

I donno hey! I think the game just throttles you now and then! Urges you to buy slices as they are available at a premium rate! Or it's just completely random. I'm back to finding a few slices a day again, but I definitely found more when I just started!