pizza. It's not hard to get something edible but it's really hard to get perfect. Either the cook faster than bottom or vice versa, or the dough bubbles or one side cooks faster or the toppings fall off in transfer or the outsides are cooked more than the middle (big problem in the kamado because the top vent is in the middle so there isn't as much air moving over the middle.)
If I wasn't so picky, it wouldn't bother me but I like it to be perfect.