What is your favorite feature of jQuery?

Chaining! Huge jQuery chains are amazing. Sometimes I can't stop. It feels almost like doing everything in one line (you want to, don't deny it).

this.lasso = $('<div/>')
    .css({ position: 'absolute', overflow: 'hidden' })
    .addClass('ui-crop-lasso')
    .hide()
    .appendTo('body')
    .resizable({
        handles: 'all',
        start: setLasso,
        stop: setLasso,
        resize: setLasso,
        minHeight: 50,
        minWidth: 50
    })
    .draggable({
        containment: el,
        cursorAt: 'move',
        drag: setLasso
    });

Try it out, you'll be addicted in no time.