I'm always one of the last to board...The plane will have to fit the total number of carryons by all pax. The stress saved is well worth risking waiting 5 minutes at the end before being able to collect your stuff from row 97.
That's unless I am already at the gate and we're being bussed to the plane- then invariably I want to be among the first so that I can grab one of the 4 seats!