Presumably from those long gone days when they were sitting behind an engine and literally ramming the throttle into the firewall for maximum power?

IIRC AA uses some of it's 757's into places like Vail where the relatively high power and rate of climb from high altitude airfields is a big plus. They also, I think, used to be one of the few types used at SNA, which IIRC was a noise abatement issue - it was always a little disconcerting to feel the power being cut back very early after a particularly quick initial climb.

Following jenbels comments about lightly loaded aircraft, I remember being impressed by a Swissair A310 coming out of GVA one Sunday morning many years ago with about 10 passengers.