Puns have strength because humor, for me, is all about the
subversion of expectations.
Language, in its rules and usage have built in expectations.
It is taking those formal structures and looking at them in a new and
surprising way in which puns have power. It may seem subordinate humor, but I
take great joy out of it.
A secondary consideration is that in punning, there is no
object to the joke. There is no one to feel bad as the pun is not at the expense
of anyone. It is neutral and self-contained. The only person you have to apologize
to is the one who heard the pun in the first place.