The real trick to roulette is to get lucky, then quit while you're ahead. Every spin has a 1 in 37 (for European) or 1 in 38 (for American) chance of landing in a given pocket.

While mathematics can help you understand the odds and probabilities of different outcomes in a roulette game, there is no guaranteed way to win using mathematics alone.

There is no single "most important" element as all film components  story, characters, acting, direction, production quality, pacing, emotional impact, relatability, and originality  contribute to its overall quality. However, many argue that a compelling story is at the heart of a great movie.