“They say your muscles have memory. Once you've trained your arms to swing a tennis racket or your legs to ride a bike, you can quit for a while - years even - and all it takes is picking up a racket or jumping on a bike again and your muscles remember what to do. They snap right back to performing the way you taught them.

The heart is a muscle, too. And I've been training mine since I was a kid to fall in love with one particular person.”