Actually, Mr Snupy, Valentine's Day goes a lot further back than that - back to the 14th C. Chaucer's Parliament of Fowls is supposed to have been composed for St Valentine's. Pepys's diary mentions it a lot.
Also, driving on the left, according to some experts, was what the Romans did, and quite possibly what early settlers in America did too! We just saw no reason to muck about with an established custom.
Amongst our inventions you might have mentioned baseball - yes! - baseball! Jane Austen, for example, mentions it in Northanger Abbey (written in the late 1790s), Chapter I.
Best regards,
Howard the Pedant.