I for one am just simply not trying anymore, because I know the answer will always be a "no" anyway. Itīs a pity really, and I suppose a good number of pilots donīt like it either.
What I am doing however, is asking a member of the Cabin Crew (during the flight) if I may have a quick chat with the flightdeck crew once we are at the gate. In most cases I am welcomed to stop by, at the same time however I am not disappointed if my request is declined. I understand that pilots are eager to get out of their seats after a longhaul flight or have rather tight turn-around times etc., hence I make it a point to stay just for a few minutes and I always make sure the crew knows how much I appreciate it.
I have met a great number of very interesting people that way, and itīs really too bad we (the interested public) are not allowed to have the jump seat anymore if the Captain and F/O are okay with it, but oh well.