How opposite are opposites?

I'm always quite confused on opposites.
They're always in complementary elements (earth/water or fire/air) so there is an implication that they could work but astrologers often seem to disagree on whether opposites work or not.

Some say that with a little adjustement they get along really well and each have something the other is missing and really needs. They also say opposites create a lot of attraction but irritaion too.

Personally I don't think opposites are that different. They usually just come at one issue from different sides. For example, Cancer and Capricorn both love family and stability but Cancer offers emotional stability and focuses on the actual home life while Capricorn offers financial stability and providing for the family through work. So long as both signs can see they're working for the same thing then surely they're covering all bases and are almost meant to be a team and complete each other.

I also don't really know what makes some opposites so opposite. I don't know too many aquas/leos so I'm not sure about them or taurus/scorpio.
Virgo/Pisces for example I believe are opposite because Pisces will be too sensitive to Virgo's criticisms (but surely the other water signs are sensitive to criticism too) and virgo is too practical and detailed for Pisces fantasy world (but the other earth signs are practical as well so why are they supposed to like pisces and virgo isn't?)

In short. I am unsure on opposites