An end effector is disclosed. The end effector can include a staple cartridge comprising a staple comprising a leg. The end effector can also include an anvil comprising a tissue compression surface, wherein a plurality of pockets are defined in the tissue compression surface, and wherein the plurality of pockets comprises a pocket comprising a cup configured to form the leg. The cup can comprise a boundary surface comprising a perimeter, a depth profile defining the depth of the cup along the length thereof, a first curved sidewall extending from the perimeter toward the depth profile, and a second curved sidewall extending from the perimeter toward the depth profile. The first and second curved sidewalls can intersect the perimeter at a constant angle along a majority of the length thereof.
