I know Machiavelli said you should never outshine your master, but what does that even mean? Here, I guess your master is anyone you are in a dependent relationship with. Or perhaps anyone you often get favors from. I think the real rule should be; never let your master know that you are doing all you can to outshine him, especially if you are fully dependent in that relationship or if you are yourself up to nothing tangible.
But the ultimate feat is to outshine your master, by becoming a master yourself someday; unless you intend on being a slave forever. It might not be in a competing way, perhaps, many of us are in ourselves master-destined. And not wanting to outshine your master means having to apologize or feel remorse for your successes. It means that you should self-destruct. It means that you should endure or even inflict on yourself-mediocrity. Never apologize for your success; you are better than those that you are better than, and those that are better than you are better than you.