yeah, i kinda have the same thing happen to me:
every monday of course is chest day. I load up the hammer with 3 aside and some loose change, and crank out a bunch of reps...like 12 or so. After a few sets, i unload to weight. This guy, roughly 45, who is always in the gym, jumps on, loads it up to exactly the weight i had on at my heaviest set, and cranks out one half rep, sometimes a complete full rep. I thnk he does it to "show the young guys" he can match them. 12 reps v. one half rep. I soooo wanna say to him, "you will hit your chest better by dropping weight and getting more reps" .... but i hate to preach. He so need to hear it. It is almost annoying to witness this shit.