The government (sing) are…
Manchester United (sing) are…
England (sing) are…
Neither of them (sing) are…
I hate it.
Whereas data and agenda, for that matter, have pretty much transmogrified into English words and singular ones, to boot. Few would now talk about a datum or agendum.
That said, I hate hearing octopi as a plural of octopus. If you're going to be a pedant about it – the plural would surely be octopodes – but octopus, too, has become an English (singular) word, so I reckon octopuses is perefetcly acceptable and generally better.
I'm going to the positive pedantry thread and avoid being a cross-patch today. 