Most people say g4 is the worst opening move, but I think it's f3 by a long shot. Quite a few elite players think this as well, if that means anything to you.
g4 at least tries to get some sort of an attack and allows a piece (the bishop) to develop. It's also considered a book move by the engine, showing that it has at least some ideas. Granted, that "idea" is mainly to confuse the opponent, but still.
Meanwhile, f3 exposes the king, greatly hinders development, and doesn't even try to form an attack in any way. That, and it's one of only a few first moves that are considered a mistake, meaning there's basically no reason to play it unless you really want a challenge.
whats the worst opeing move in general like dont have any openings no advantage whatsoever