You can play horrible, and still play fast. No one needs 5 minutes to line up *any* shot. Before I get to the ball, 90% of the time I already know which club I'm hitting next. Then it's align body, 2-3 practice swings, and let 'er fly. The other issue with people is 2 guys in a cart, approximately the same distance from the hole, but one on the left side of the fairway one on the right. Left idiot drives cart to his ball, while right idiot sits in the cart and does nothing but watch. Left idiot *finally* hits his shot, it may be good, it may be crap. Then left idiot wipes off his club, puts it in the cart, and then drives over to right idiot's ball. Repeat process for right idiot. Repeat entire process until both balls have finally made it onto the green. Then they spend 5 minutes lining up a 25' putt. Hey geniuses, even the pros rarely make 25 foot putts, and the only reason they are is because they are playing for thousands of dollar. Get it close, take your two putt like you were going to end up with anyway and get your ass to the next tee box.
The way I make sure to keep things moving: Drive to ball furthest from the hole. Person making shot from there pulls 2-3 clubs out of their bag, and the other person takes the cart to their ball. The first guy hits his shot, and starts walking toward his ball. Person number two hits shot while person number one is walking, and starts driving to meet them after shot is taken. You can shave an hour off the game just by doing that. There are holes where even though I have a cart, I will end up walking half the hole. I actually prefer to walk the course, but hate carrying the bag.
Also: Wipe your clubs down, and figure out your score on the next tee box, not while still on the fairway/green.