SW loading is good, but since most find the front of the plane more desireable, there is a jam in aisle at the front. Let me on first and I won’t be slowing things down as I go sit in the back at a window seat.
I usually go to the back too; if the flight is nearly full, odds for an unoccupied center seat next to you improves. SW is not perfect, but definitely the most efficient. I remember their prior boarding system. The cattle yard formed at the gate before boarding. They obviously figured out how to make it easier.
(BTW - correction of my previous post - there were 8 heads in Joe Pesci’s duffle bag. )