Why it matters
Averages hide the business: "our customers" usually contains a segment worth five times the rest, a segment that churns instantly, and a segment you lose money serving. Decisions made on the blend misprice, mis-target and mis-serve all of them at once.
How it works
Useful segments differ in behaviour you can act on (what they buy, why, how much, how often) not just demographics. A handful beats a taxonomy: each segment should imply a different action (message, offer, service level), or it's a label, not a segment.
What to do about it
Split last year's customers by profit and by need. Name the segment you'd clone if you could, then point next quarter's marketing at finding more of exactly them.
