I was watching a show tonight where they wondered about the opposite of "interesting." My thought was "boring," but the question piqued my interest and I found this website on opposites. While many seemed good, some of them were quite odd to me. For example, is "lady" the opposite of "gentleman" to you? Or is "mean" the opposite of "generous?" Take a look at it and see what other odd/wrong ones you can find.
It depends on your definition of "opposite". Some words don't really have an opposite; is an adult really the opposite of a child, for instance? Is a man the opposite of a woman? I'd say man and woman are similar, not opposites, although I can see why they're listed.
One particular pairing that I noticed is active/lazy. That really is wrong. Another is to amuse/to bore.
Build a man a fire and he's warm for a day. Set a man on fire and he's warm for the rest of his life.
I like the Discworld conceit where "sober" isn't the opposite of "drunk" it's merely the absence of "drunk" and the opposite of "drunk" is "knurd" the state that is on the opposite side of "sober" as far as "drunk" is on this side.