Cancer begins at the summer solstice — the longest day, and also the day the light starts shrinking. That gives Cancer an undertone no other sign has: it knows from the outset that after the peak comes the descent. So Cancer's core isn't emotionality, it's protection: put the important things away safely, because conditions will change.
You'll recognise it here: you remember the small stuff — who said what, who was having a bad day — and you assume everyone else does too; your definition of home is stricter than most, which isn't clinginess but a need for one place where you don't have to be on guard; and you look after people first and then keep a private ledger you never show them.
Running well, Cancer is what gives a group a sense of belonging: what you build isn't efficiency, it's somewhere to come back to, and that outlasts any project. Blocked, protection becomes a shell — keeping everyone out is easier than sorting, so you end up lonely and unwilling to open; or care becomes a way of buying against being left, at which point it has conditions on it. The most useful sentence Cancer can practise is 'I need' — two words that work better than any hint, and that make the ledger disappear.
