I actually didn't think it was about the carp, that comment was in reference to (to paraphrase) not generating role play. It might not have been inspiring role play but it was something anyway.
As far as the Character acting in a manner befitting of his profession you should consider that nobody is professional 24/7 unless they really don't have a life. If you are a dour mercenary just waiting for the next battle it does not leave a lot of room for anything else. Go to the bathhouse and get into a fight with that other woman who steals your soap. Conceding that there are neither bathhouses nor soap in the game. When you are about your profession focus on it, crack related jokes, offer or ask for advice from others doing the same. Compare notes or tell tall tales.
If you have to plan everything out you will miss a lot of great stuff. It doesn't have to be too hard.
But what do I know. I don't get involved in great plots and melodramas. I just go along and try to have some fun.