No, in a general philosophical sense, that’s an arbitrary decision you get to make, unless you choose to surrender that decision to some particular credo, code, person or organization (of which there are several with opinions you could surrender to).
For example, a sports coach may well want you to bring your “A” game to every game, while another might tell you to save it for the playoffs, or you might choose to tell all coaches to have fun but you have no interest in even trying out for their team. A coach is great when they help you do something you want to do, but they can also be someone manipulating you into doing something you don’t actually want to do.
I tend to think it’s most important for people to find what they’re most interested in and/or passionate about, and to focus on that. In which case, there’s probably little use in moralizing about whether they’re playing their “A” game or not, because they’ll tend to be self-inspired. If you need to hype yourself up and struggle with your willpower, you’re probably not doing your calling (or something else is interfering).