I'm bugged by the misuse of "2.0". There is no second "web". And when there is an actual second version of something, it's not necessarily good, so I don't get how putting "2.0" on something that isn't literally a second version of a program is supposed to make that thing sound good.

Worse yet, almost nobody pronounces it anywhere near correctly. It has no letters in it, people! It has only a "point" between two separate numerical digits!

Similar to the "misuse rather than overuse" being what bugs me in that case, my main problem with "fail" is when it's used not as an interjection but in a sentence as a noun.

"Woo" also bugs me not through overuse but because it's often done wrong. The complete form is "woo-woo". Singlifying the doubled syllable not only shows laziness & sloppiness, and makes it not the same thing anymore, but also bumps into the spelling and sound of another word which got there first. (I've even seen this pop up in a thread that was all about certain sources of advice on how to woo people!)

There is one place I know of where "fail" and "woo" can be good things. It's a separate forum website from this one, where people pride themselves on their logical objectivity and are very negative about ideas that lack logical or empirical support and the people who fall for them. Both the ideas and the people are usually called "woos", and when a "woo" fails to provide support for his/her "woo" ideas or answer pointed questions about them or counter a solid refutation of them, it's called a "fail". Or at least, that's apparently how the authors who use these words see it. But to me, it's often a sign that the author who's flinging those epithets around is the real woo-fail in the situation, having thrown away logic and objectivity in favor of personal put-downs and premature/feigned victory dances. So in those cases I like seeing "woo/fail" because it's a useful line in the sand, my signal that there's simply no reasoning with that author anymore so I might as well not bother to try.