My advice: don't get too hung up on the 'why's in Italy.
Why does that one official at the Anagrafe (registry office) always seem to say no while her colleague next door says yes to the same request? Why exactly is it dangerous to open a window when we're all sweating inside?
“Così vanno le cose” ('that's the way things are') is the best answer anyone might be able to give you.
But we can at least offer you another way to ask the question: come mai?
The phrase literally means 'how ever…' and it's a synonym for perché, the first way most of us learn to say 'why' in Italian.
Come mai non siete venuti alla festa?
Why didn't you guys come to the party?
Just like perché, you can use it to start a longer question or all on its own.
Non venite? Come mai?
You guys aren't coming? Why not?
But come mai is different to perché in a couple of ways: a bit like saying 'why on earth…' in English, it can imply that what you're asking about is somehow unexpected or unlikely.
Come mai viene la grandine? È quasi maggio!
Why on earth is it hailing? It's nearly May!
It's not limited to the questions no one can answer, though. You'll hear come mai just as often when someone is simply curious how something came about – like asking, 'how come?'
Tu sei americana ma vivi in Italia. Come mai?
You're American but you live in Italy. How come?
Take the example above: asking 'why' (or perché) in that context might sound like you were demanding a justification, whereas 'how come' (come mai) shows that you want the backstory. I like to think that come mai invites a longer, chattier answer than perché would.
The last and biggest distinction between the two is that while perché is both question and answer ('why' and 'because'), come mai is question only: you never use it to start an explanation.
You can, however, conclude with a laconic chissà come mai, 'who knows why' – for some reason, it's a phrase I often find myself turning to in Rome.
Do you have a favourite Italian word you'd like us to feature? If so, please email us with your suggestion.