Senna is brilliant because it's about universally relatable themes - ambition, rivalry, faith, loss, etc - so it doesn't matter if you know nothing about Formula 1. It's also brilliant because it relies on archive footage with thrilling immediacy rather than older talking heads reminiscing. In short, it's absolutely riveting, and as you say, an incredible tribute to a Brazillian national hero (that bit when you see his lifelong rival Prost as a pallbearer at the end moved me to tears).