Worse imho is the "glasses", "pants", "pliers", "scissors", etc thing. Single object with plural name just because it happens to be made of two similar parts. Most objects are made of multiple parts though and they get a singular name just fine. That and the "double u", why not "we"??
EDIT: Now that I think about it there is another one that is hard for me, even it I know it is the correct form in English: visa (singular) and visas (plural). In my mother tongue it follows the same pattern as datum and data, it's Visum (singular) and Visa (plural).