Xalatan eye drops for glaucoma.
I didn't realize I forgot them until I unpacked for the night in Barcelona. I went to the local Farmacia and I was able to buy the same 1.5ml bottle for 18 Euros. The exact same bottle costs $108 here in the U.S.
I once forgot a dress belt and I also once didn't pack a sport coat. I packed my tuxedo but I didn't want to wear that to the supper club. A kind Moose loaned me his white dinner jacket and everything worked out fine. It just took him a while to get that "Old Mike Smell" out of it.