Borrowing the title of this thread from a comment in the same. Would love to hear from an Italian here as to what word or phrase is causing the confusion.

 

in some regions of Italy (and France as well) we use "terribile" as a way of saying "terribly good". So depending on context, it may mean that the watch is awesome or really bad

 

Haha! Yes I saw this one too, made me smile, good use of slang in an ad.

“It’s not bad meaning bad, but bad meaning good!”

To quote Run DMC

 

Same on here in Spain. But to be literally correct, the add should say “Terrific good example”.
Another example is the word horrifying used in Andalucia, like the following example; “We had an horrifying good time”, meaning a real good time.

 

Seems to be the Italian equivalent of "Terrific!", now fallen out of use and replaced by the American import "Awesome!".

 

Reverse psychology to make you want it more?

 

Possibly 'tremendo', which can be translated as 'fantastic, marvellous' but also as 'terrible, awful'