I also fly a PA28 Archer III
After gaining my PPL, I desperately wanted to take both of my parents up for a trip. I'm fairly heavy (114kg) and my parents are not exactly on the small side. After a weight and balance calculation I found that even with fuel up to the tabs, we would be 190lbs over weight. Unfortunately mum had to stay behind, but even with just the two of us we were only 10lbs underload. I must say that I definately would not have wanted to take the aircraft any heavier. At nearly MTOW, performance was lowsy. It was a warm, windless day and I think I can say in all Honesty that an extra 190lbs would have caused us to spend the next hour, red faced, in the adjacent field.