Actually David V, the wee 150 could climb with full flap. In my very, very early days, I flew all the way to Downwind on a go-round with Flap 40. (One of those extended newbie brain-farts) The climb was slow, but not non-existent. That said, it felt very odd. And yes, I do know it's not the best way to carry on.
But aren't they forgiving little machines??