Glass Pants

A man saw a sign in a clothing store which said 'We sell everything!' The guy walked up to the clerk and asked her for some glass pants.
The woman replied, 'Sorry sir we don't sell those'.
The man argued that the sign stated that the store sold everything.
The woman remarked that glass pants did not even exist.
The man went home, and came back to the store wearing a pair of glass pants. The man said triumphantly, 'See, I told you that they existed!'
The woman said, 'At first I thought you were crazy... but now I see you're nuts!'