Where you actually meet it
Venerdì 17 is the date, and the arithmetic guarantees it turns up. The seventeenth of the month works through all seven weekdays across twelve months, so every year gets at least one Friday the 17th and some get three. Alitalia, which flew until October 2021, numbered its cabins straight from row 16 to row 18. Renault, launching a coupé into a market that would not buy a car called seventeen, badged the R17 as the R177 for Italian showrooms.
The lotto is where Italian numbers become a daily habit rather than an avoidance. Genoa legalised the game in 1644, Venice held its first official draw on 5 April 1734, and Naples took it up and never let go. The modern draw uses 90 numbers across ten city wheels plus a national one, extracted in Rome, Milan and Naples. Feeding it is the smorfia napoletana, a dream dictionary that matches whatever you saw in your sleep to a number between 1 and 90. Forty-eight is 'o muorto che parla, the dead man who speaks.
At Christmas the same ninety numbers come back out as tombola, played at the kitchen table with the smorfia meaning called alongside the digit. Motor racing supplies the bleakest seventeen story. Ugo Sivocci died at Monza in September 1923 testing an Alfa Romeo P1 carrying number 17, and the four-leaf clover he had painted on his cars was afterwards redrawn on a triangle instead of a square in his memory. The often-repeated claim that Italian racing then retired the number 17 for good is disputed and poorly sourced.