Face Tickling: Annoying or Torturous?

I've had two separate past girlfriends marvel, after meticulous investigation, that the only part of my body that wasn't ticklish was my face (ears and neck excepted). I'd be reluctant to let anyone explore that possibility too thoroughly, however, lest they discern previously undiscovered ticklishness there.

Annoying, but gets me into a giggle fit so idk... it is still more annoying than enjoyable. I would take it as a way to tease me or tease a 'lee.