Someone once told me that the number of words a culture has for a particular idea or phenomena reflects its importance to that culture. The Yupik Eskimos are reported to have 24 words for snow, which makes sense since much of their lives hang on understanding and accurately adapting to the snow conditions around them.
If 24 words for snow is one yardstick of serious importance, then Judaism’s lexicon for “sin” is relatively paltry: averah (crossing over the line of the straight and narrow path), het (the missing the mark), ahvon (wrong doing), and peshe (negligence).
This is not a foolproof system, of course. Christianity has built its entire theology around sin and yet only has one word for sin (its modifiers, like “mortal” and “original” notwithstanding).

I think Judaism’s sin lexicon is telling. Though these words certainly focus us on human frailty and failure, they contain within them the potential for rectification. Think of it as if you were on a path and wandered off, intentionally or by accident. You could always just redirect your steps to get back on the path. If you missed the mark, you could realign your direction. If you did wrong, you can start to do right. If you were negligent, you can be more careful next time. That is why, while I agree with Rabbi Waxman that we must take more responsibility for our actions, I disagree that focusing on the idea of sin to indict does little to truly reform us.
Rather, I believe we are better helped by remembering that God created us pure, in God’s image, with the potential for great good. God indeed made us with the tendency to mess up, sometimes more badly than other times, but also with the capacity to constantly grow and change. This is one explanation of the shofar blasts: we start out whole (the whole note of the tekiah), become broken (the triple shevarim) then fractured (the nine note teruah), but can always come back to an even greater wholeness (the great tekiah gedolah).

During these 10 days (and the weeks leading up to it) we are to concentrate on our failings and weaknesses, not to wrack ourselves with indicting guilt but to see our mistakes clearly in order to correct them, where possible, in the present and avert them in the future, on our journey back to our original purity and wholeness. That is why, for me, these “sin” words do not conjure guilt as much as regret, responsibility and the desire for improvement.
I am not exactly sure where we Jews got such a bad rap for being a guilt-ridden community. Our theology certainly does not instill it. Just the opposite. Judaism is a relatively guilt-free religion. Most of the year we focus on joy and rejoicing (for which there are many words in the Jewish lexicon).
In fact, we should be filled with joy even on (or maybe especially on) Rosh Hashanah and Yom Kippur. We trust that God will forgive us as long as we meet God half way, by doing the inner work of reflection (honestly acknowledging our failings), repentance ( regretting our deeds and deciding to change our ways), and atonement (seeking forgiveness of others and of God). Because God loves us and our ancestors, God forgives us, just as a good and loving parent would. How could you not be joyful about that?