The lines on your putter are critical to how you aim. Lines can help or hurt depending on how your eyes interpret them: it is a question of whether to have aim lines at all, where they are placed, and how many you use. The pattern of lines changes which part of the putter you look at, and that changes your perspective of the hosel, the putter head, everything. Lines in general: tend to make golfers aim left. Farther back: the farther back the lines sit on the putter, the more they aim you left. Near the top-line: influence aim less than lines placed nearer the bottom cavity. No lines: tends to create a right aim bias.