To emphasize Doug's point....
I'm building my "superstar" ship CO from the ground up (based on the example advancement pattern in the PG, he has 21 advancements throughout his 13 year career), and I had always envisioned him with a limited amount of psychology experience based on his learning how criminals work (through independent study, etc.). So, I purchased Medicine (psychology) +1 for 3 picks.
This character also plays the pan flute (a hobby that he kept from childhood). So, I considered that he was finally decent enough a dozen advancements into his Starfleet career to warrant buying Entertain - Play Instrument (Pan Flute) +1.
Davy Jones
"Frightened? My dear, you are looking at a man who has laughed in the face of death, sneered at doom, and chuckled at catastrophe! I was petrified."
-- The Wizard of Oz