Any of you guys play Pool, Billiards or Snooker?
To play a ball with top-spin, forward roll, the ball is struck above its equator - equivalent to putting on the up swing. The ball begins to roll almost immediately.
To play a ball with back-spin, backward roll, the ball is struck below the equator - equivalent to putting on the downswing. In golf the ball hops, skids and then begins to roll forward as its momentum overcomes inertia and friction - in the other, cue based games, the ball will simply skid until friction "bites" allowing backspin momentum to overcome the balls inertia. In golf the intention is to get the ball to roll forward, yet the mechanics are poor and physical principles are non-optimal. Whereas in the cue based games the mechanics and physics are optimised to achieve the opposite to a forward rolling golf putt and they promote the exact opposite.
To play the ball without intentionally imparting spin you would hit it on its equator - equivalent to a completely flat push through impact with the putter. The ball will skid as it fights friction before the loss of friction and momentum allow it to overcome its inertia and roll forwards.
Putting on the up stroke promotes a forward roll whereas the alternatives mentioned do not. Add C grooves to your putter and the effect is enhanced - as Mr Swash discovered.