First, of all, FIRE THAT TRAVEL AGENT and if he's not the owner of his own company, try to have a serious discussion with his manager about how inappropriate your experience was.

For me, the most important thing (which isn't a feature of all premium cabins, so I try to pick aircraft that are configured this way, usually 1-2-1) is 100% direct aisle access. It's nice to have an aisle seat with a window but more importantly as I travel alone, I don't want to be a climber or a climbee on long flights. I want to be able to get up freely without disturbing a seatmate or neighbor and I also don't want some stranger to be constantly waking me up to trying to wedge his/her body out of the seat without touching me or knocking over my wine glass. [If the aircraft's configuration is 2-2-2, I try to get one of the seats in the center section and then I'll move to a window seat only if the seat next to me is empty. I consider 2-3-2 to be inappropriate for business class, even on "regional" flights.]

Sleep