1 ½ hour flight out (American Eagle), wonderful Flight Attendant, up & down the aisle very nice an professional (just one FA on the RJ). 1 ½ hour flight back (American Eagle), it was like there was not a Flight Attendant on the flight. He did a pre-takeoff check, then never got up from his jump seat the rest of the flight. The flight was a little bumpy, nothing that would impact an able-bodied adult from walking around & I didn’t hear any announcements about turbulence or that there wouldn't be beverage due to _____ (fill in the blank). Even after the announcement that the Flight Attendant would be going through the cabin for pre-landing check, he still never left the jump seat. (No, I didn’t ring the call button to ask for a drink) I’m guessing maybe he was queasy and didn’t want to walk around? Even if that’s the case why not announce something? What are your thoughts on why a Flight Attendant would stay in the jump seat the entire flight?