Since I have become a working mom I suddenly have a lot less time for things like this, but this morning I heard something interesting (on TV) that I would like to comment on.
It was an episode of an American drama-series. Elaine had been out on a date with a guy who turned out to be a jerk. She didn't want to see him again, but he looked her up a few days later, begging for a new date. He said: "I'll be a perfect gentleman". It was her answer that intrigued me. She said: "You don't be a gentleman, you either are one, or you're not."
It seems that the infinitive be, as opposed to the finite form are, here, signals a non-permanent state, as opposed to an inborn characteristic, signalled by the finite form. This distinction reminds me of the distinction between the Spanish verbs ser and estar (both translatable by to be); ser is used with predicative complements that signal permanent characteristics (beautiful, kind, funny, etc.), while estar is used for temporary states (angry, sad, sick, etc.). (In Spanish, however, estar is excluded when the predicative complement is a noun phrase, as in the present case).
I ask myself (and anyone that may have an oppinion about it) whether this use of the infinitive be would be at all possible if it weren't for the immediately preceding sentence in this particular context (i.e. "I'll be a perfect gentleman").