Otto misses something, but what?
Today's Beetle Bailey has an interesting example of misnegation:
Surely what Otto misses are "the days when the mailman came". Or he misses "it when the mailman doesn't come".
This is the kind of construction - one without an overtly negative, that is, no negative prefix, verb - where misnegation, generally over negation, is prone to occur. Things like "no head injury is too trivial to be ignored", for instance. But it also occurs in constructions like "can't fail to miss", or "cannot be underestimated."
Note: this is not negative concord, where (except in Standard English) two overtly negative markers reinforce each other, as in "we don't need no stinking badges". And it's not genuine double negation, as in "I cannot help but note..." or "I don't never go to church, I'm there every first Sunday!" This is something subtler and hard to notice - in fact, often it isn't noticed.
(For discussion by people who actually understand what they're talking about, see these Language Log posts on the topic and especially this one on this very comic.)