is without a doubt, Papa John's. and Dominoes when I'm in Taiwan. Here are three things about my preferred pizza:
-jalepenos should be on there
-the cheese should not look like elmer's glue (i.e. it should not be ALL OVER THE PLACE, runny and undercooked)
-the crust should be a nice balance of crunchy + chewy, but that's only if it's a regular. thin crust is always awesome when i'm in a crunchy-only kind of mood.
p.s. I hate when a slice wasn't separated thoroughly enough from another slice, and i have to pull it apart, and when i do, a glorious glob of cheese/pepperoni slides off the tip of MY slice while staying on its neighbor slice (or in the worst case, remaining on the damn cardboard). I think of it like a wishbone-pulling kind of deal, except with pizzas.
