i teach economics at unlv three times per week. last monday, at the beginning of class, i cheerfully asked my students how their weekend had been. one young man said that his weekend had not been so good. he had his wisdom teeth removed. the young man then proceeded to ask me why i always seemed to be so cheerful.

我在内华达大学拉斯维加斯分校教经济学，每周上三次课。上周一，在刚开始上课的时候，我兴致勃勃地问学生们周末过得怎么样。一个男生说，他的周末不太愉快，因为他的智齿被拔掉了，结果让他痛了一整天。然后，他又问我为何我总能保持那么快乐的心情。

his question reminded me of something id read somewhere before: every morning when you get up, you have a choice about how you want to approach life that day, i said. i choose to be cheerful.

他的问题使我想起了一句不知出处的话：每天早上，当你起床的时候，你可以选择如何面对一天的生活，我说：我选择快乐。

let me give you an example, i continued, addressing all sixty students in the class. in addition to teaching here at unlv, i also teach out at the community college in henderson, 17 miles down the freeway from where i live.

one day a few weeks ago i drove those 17 miles to henderson. i exited the freeway and turned onto college drive. i only had to drive another quarter mile down the road to the college. but just then my car died. i tried to start it again, but the engine wouldnt turn over. so i put my flashers on, grabbed my books, and marched down the road to the college.