Hee, our oversized Marley was a jumper, and seeing as he was at his full size at about 8 months old, this was a problem. He only jumps nowadays if he completely loses it, and that's becoming increasingly rare. He doesn't mean any harm, but he forgets his size. For people who aren't dog lovers, seeing 100lb of fur, drool and muscle running towards them can be a bit disconcerting.
Oh goodness, seeing a happy doggy (whether 15 lbs or 115 lbs) tongue sticking out, tail wagging, and running toward you, that's the greatest sight. I'd get strange looks because I'd get right down on the ground with the dog(s).