564. Centerrifical Force
The way your eyes immediately tell you if a card is rightfully centered enough for you personally, independent of what other collectors or TPGs may think.
Seemingly 90% of the graded cards (post-war) I buy have OC qualifiers, but the vast majority of those are ones than no 'normal' collector would've called off-centered in the days before TPGs ruined (
) everything. If a card looks decently centered enough to my eye, and I can get it at a low price, I jump.
(All of this is thrown out the window with the 1972 Topps set, though, because I hope to assemble a nice one as close to perfectly centered as possible.)