Another way to think of it is, 'What's the value of hammering in your rail-road stakes all the way?' Well, that's important, right, you don't want the track to warp and buckle and make trains crash, right? So railroad stakes should be hammered in fully, every time. 'Well then [i]why aren't we hammering in rail-road stakes everywhere, if they're so good?[/i]' I don't have **ANY** in my house! Oh, shit! Is my house going to crash?!? 

In most conversations (meaning the stunning majority of them), 'proof' is as useless as a railroad tie in your living room. Useless things are often detrimental. In the case of 'proof,' that comes from the fact that a person who tries to prove every damn thing in the world *must* believe he [b]knows[/b] every damn thing in the world. Such a person is probably even more insufferable than I am.