I used the "F" mug yesterday.
Would you believe we just put away our Christmas mugs this week? When we undecorated from Christmas back in the beginning of January, we decided we'd like to keep the Christmas mugs out a while longer and enjoy them. So now we have all our regular old coffee cups back into rotation. This "F" mug is however a new addition - we "won" this mug at our family Christmas party. (We play a game where we all bring a $1 gift that is wrapped anonymously, then we all draw numbers and choose a gift or steal from someone else - I'm sure many of you are familiar with this game.) Anyway, the "F" mug was actually our own contribution to the game, but after perusing what else there was to offer, we decided we wanted the mug. You never know from year to year what is going to show up at "the game" - all kinds of stuff like fake arm tattoos, a back scratcher made from an actual turkey foot (posted a pic of that here!), marshmallow blow guns, and a giant lump of coal, to name a few of the more memorable items that have shown up.
We like the "F" mug because of the ambiguity of it. On any given day, the user of the mug can decide for themselves what that "F" stands for... :-P