Last spring I did my longest ride (at that time) 60 mi. the last half was very hilly (for our area) with a headwind about as bad as you can get. Toward the end of the ride several guys drafted off of me, then they'd zoom off to the next person to hide behind.
I wanted to say "Hey if you can go this slow behind me for a few minutes, Why can't you ride in front of me and give ME a break". Next time I will say something. It is only right.