做好事如同背负重物而登山，志向虽已确立，但总是担心力不从心；干坏事如同骑马下山，虽然未加鞭，但却欲驻足而难以自禁。

The worth of a psychological theory is measured by its usefulness.

Memory is what we thought we’d forgotten; it’s also what we thought we’d remember.