Guastafeste literally translates to "party wrecker" or "spoiler of festivities," but it's commonly used to mean "party pooper" or "killjoy."
In the song, Diodato sings, "E non dirmi che sono il solito guastafeste" (And don't tell me I'm the usual party pooper). He uses this word to preemptively address someone who might criticize his melancholic or nostalgic mood, suggesting he's aware he might be perceived as a bit of a downer. It's an interesting, slightly informal word that captures a relatable feeling.
Have you ever felt stuck in a rut, where even your favorite things don't bring you joy? That's the feeling Diodato captures in "Vieni A Ridere Di Me," which translates to "Come and Laugh at Me." The song paints a picture of a lonely day in Rome, where the singer is trapped inside, trying to pass the time by reading, watching shows, and cooking, but nothing works. He feels foolish and lost in his own thoughts.
But this isn't just a sad song! The chorus is a powerful invitation to a special someone. By asking them to "come and laugh at me," he's not asking to be made fun of. Instead, it's a vulnerable plea to share a moment, to break the loneliness with shared laughter. He realizes he doesn't want to forget this person anymore, comparing them to a "porto a cui tornare" (a port to return to)—a safe and comforting presence he deeply misses.