I think people lie in order to gain or keep an advantage. That is, the truth may damage their status or hinder their opportunities (eg. "he has a girlfriend"!)
I think some men feel they have to keep up a show of being cool/nice/strong/rich/honest/single/etc. So finding out what is true and real takes pateince and time (viz. Plato's "Symposium").
And Moscal's comment is worth noting... because people do show their true colours when faced with adversity!