I'm a wee little bit obsessed with passamezzi at present.
A lot of the passamezzo mutanze don't look wildly interesting on paper. Many of them feel ok in solo practice, but nothing special. Any many of them - even the simplest - come spectacularly to life when danced with a partner, who is doing the passegio.
Because the dancers are close together in the passamezzo - close enough to touch hands - and because both parties move at once - one in passegio, circling left and right; one in mutanza, typically zigzagging, sometimes turning - and because their steps are dissimilar - the passegio slow, with one rhythm; the mutanza faster, with quite different rhythms - the interactions between the two dancers are subtle, rapid, and endlessly varied. Make the most of them!
In a canario, one can practice mutanze alone, and have it vary little when one performs for a partner. It's nice to have one's audience right there, and lovely - in a conversational improvisation - to be able to riff on each other's ideas, in turn. But to practice alone one must simply imagine a partner standing in about the right spot, and drill away.
For the passamezzo, I increasingly feel that solo practice will have more limited value. It's necessary (for me) to get the more complicated patterns of steps into the feet. But it won't do for figuring out how to dance: what the significance of each movement is, where to direct the attention, when to linger, when to show off. These mutanze feel so very different with a partner right there and moving too, sometimes together, sometimes in opposition. The element of conversation is more subtle but more deeply woven into the dance. No wonder they were popular!