I dont think progress is ever a straight line because the direction we will be going in the future is affected by the direction we are going now. So perhaps, the pattern of progress is more like a spiral.
If so, then the question becomes are we spiralling upwards or down?
I believe that each moment of positivity places us on the upwards spiral and each moment of negativity on the down. So its all a bit like a game of snakes and ladders except that by the way we respond to each throw of the dice, we can choose if its a ladder or a snake.