Sad face.
Look, he breaks conventions! And it is, I'd say, one of your better pieces.
The first comma, mebbe, should be a semicolon? Not a comma.
And the beginning of the second stanza needs a subject; a simple "he" could suffice.
I think that there's great emotion here, it's very alive, etc etc. However, the language is a bit flat. Look through the whole piece, and think of more interesting ways to say the same thing. The last four lines are the only ones I'd say not to try and fix; I think they work as they are. When you explore more varied language, however, don't let it make your tone more stiff or formal. Keep it as it is, real and close and honest, and then make it more poignant with words better suited for the exact situation.
Good work, mate. Keep it up.

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"Man is least himself when he talks in his own person. Give him a mask, and he will tell you the truth."-Oscar Wilde

I wasn't sure about that comma, but I wasn't sure if it should be a semicolon. Originally it was all a big paragraph I was going to make into a short story, but I broke it up into a poem because I knew it wasn't going to be long enough for me to make it a short story. Yeah, the "he" was left off because I had it all as a a big paragraph, so the subject was implied, but when I broke it up I didn't think about how it would need the subject. Oops.
The whole interesting up the words thing I'm not so sure about just because of the fact that the simplicity was something I was going for. I didn't want it be be bogged down by anything superfluous, so I tried to keep it at a lower level. I'll see about sprucing it up a bit, but I don't know how much I'll do because I like how it is now.

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"I hope to one day look back on my life and say 'I am proud of what I didn't do.'" Myself, August 01, 2007.

Well, more words won't necessarily destroy your simplicity. In fact, you can probably simplify the language by using one word to peg the meaning, neatly. Remember this: everyday language is rarely "pleasantly simple." Usually it's just mundane.

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"Man is least himself when he talks in his own person. Give him a mask, and he will tell you the truth."-Oscar Wilde

Hah, well I'll keep that in mind. I messed around with the language a bit, see how you like it.

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"I hope to one day look back on my life and say 'I am proud of what I didn't do.'" Myself, August 01, 2007.

Improved somewhat.
Go for more interesting verbs. Descriptors, adjectives, etc -- those can only go so far to put life into a poem. You may have to rework sentences in a significant way; don't be afraid to do that.

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"Man is least himself when he talks in his own person. Give him a mask, and he will tell you the truth."-Oscar Wilde

I can't think of any better verbs for what it is I am trying to convey. If you've got any, I'll see what I can do, but I've stretched my mind trying to find more. It's not that I'm afraid to rework a sentence or two, it's just that I can't think of a way to improve the sentence, so reworking it would be trivial.

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"I hope to one day look back on my life and say 'I am proud of what I didn't do.'" Myself, August 01, 2007.

MM. Yeah, take some time trying to write, in as many concise ways as possible, the same actions. See what fits. Make your brain labor. Can't help you much beyond that, except to say read a lot and buy a thesaurus and a dictionary to learn words.

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"Man is least himself when he talks in his own person. Give him a mask, and he will tell you the truth."-Oscar Wilde

I have been considered a walking thesaurus, I always carry a dictionary, and I still can't think of any better verb-usage for it.

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"I hope to one day look back on my life and say 'I am proud of what I didn't do.'" Myself, August 01, 2007.

Then you are not, in fact, a walking thesaurus. Go find one.

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"Man is least himself when he talks in his own person. Give him a mask, and he will tell you the truth."-Oscar Wilde