Like many quotes, this one from Oscar Wilde is easy to say, and casually think "Sure, that's me".
I'd say being yourself requires an incredible amount of energy. The forces of the universe conspire against you. Without knowing it, we conform in ways both large and small. When we buy a brand of any type, or expound particular beliefs, how was the decision really made?
In fact, being yourself requires a conscious effort to examine the beliefs that dictate the lifestyle we lead, the lunch we'll eat, the vacation we take, the candidate we'll vote for in an election. For each of these, there is likely someone with a vested interest trying to influence you.
How to fight it? Only by deciding conciously what you'll do. Even then, the myriad of influencers swirl around in such abundance it is hard to know where reality ends and spin begins.
Will Rogers summed it up, "Too many people spend money they haven’t earned, to buy things they don’t want, to impress people they don’t like." So the problem isn't new.
If you consistently ask yourself if what you are doing is important to you that might be a start. Everything hinges on your ability to be honest with yourself. If you can do that, you are on your way.
The rewards are fantastic once you get past the darting glances. There is nothing people have more trouble with than looking in the mirror. By being yourself you confront their anxiety over the same issue.
Don't wait for thank you cards. You won't get any. Instead thank yourself for stepping off the treadmill.
Living your life on your terms is something to be truly grateful for. Enjoy it.
But keep a wary eye on yourself. You can change, but the world won't stop trying to lure you back.