Matteo Mancuso doesn’t like to think too much—not when he has a guitar in his hands, which seems to be most of the time. “The less I think, the better,” he says. “I like to be instinctive, especially when I improvise. Most of my music is centered around improvisation, so I need to feel very free. Otherwise, I’ll be second-guessing each move I make and I’ll be judging myself.” He cites one of his f...