Where you work
Why, yes, the new secretary is attractive, or, let's suppose, your boss is a handsome devil. Our woodland friends know it's not a good idea to relieve yourself where you feed yourself. So, too, should you never get frisky with someone who occupies a cubicle near you. It's very tempting, what with their proximity, and it may go along swimmingly for a while. Then things turn south, and you have to look at the angry face of the one you dumped every day for the rest of your career. There is no worse fate.