The Imago is the unconscious image of your ideal mate.
However, it actually does not describe your best match, but instead only the kind of person you will be the most attracted to.
The closer someone matches your Imago, the more you will feel attracted to them; the less so, the weaker the attraction. So, when people talk of moments when they “felt no chemistry” with someone, that person most likely did not fit their Imago close enough to spark any attraction. The most passionate relationships are typically between people who fit each other‘s Imago well.
Ideally, you find someone who fits your Imago more or less, but is also a good match for you in terms of psychological health, personal values, Socionics compatibility*, and so forth.
*The Imago is probably the biggest reason why Duality is not as common as it ideally would be. Because, the Imago does not always fit someone’s Dual.