A heavy, straight-across fringe cuts the face into two short halves and makes it read rounder. Length is the thing you are protecting, so a fringe that removes forehead height works against you.
Curtain bangs do the opposite. Parted in the middle and sweeping outward, they leave a vertical gap down the centre and create two diagonals across the cheeks. Long side-swept bangs work on the same logic.
If you want a fringe with real weight, take it longer than feels natural — grazing the cheekbone rather than the brow — so the line it draws is diagonal rather than horizontal.