I once flew MAN - LGW for the purpose of visiting a property about a mile from the airport. It was such a long day for such a short visit that it was easier to make a day of it, go by train to Euston, tube to Victoria, train to Horley and then meet up in the afternoon/evening with friends.
Can't remember the last time before that I flew from Gatwick - possibly 1996 and the destination is no longer served.