Also, avoid direct eye contact, and never ever stare into their eyes. This is the equivalent of an oath of blood and despair.
That's something people who don't own a cat don't understand: the less you look at them, the more friendly they think you are (that's why cats love allergic persons)
You're right. The rules are not the same with your own cats. One of my cats likes long blinks (aka "eye kisses"), and for an other one it's a call to play and cuddle on the rug.