Very annoying, but when you hover over a badge on Gaming.SE, the hover state adds an extra pixel on the bottom which creates a white line between the edge of the badge box and the box shadow below it.
Exhibit A: The offense in action.
Exhibit B: The offending CSS code.
.badge { padding: 4px 8px 3px 2px; }
Exhibit C: The fixed CSS code that looks so much nicer because there's not an annoying white line.
.badge { padding: 3px 8px 3px 2px; }
Oh the humanity! How could one number cause such an outrage!?
Decrement it and let justice prevail!