I actually don't end up clicking the "reply" button on a good portion of the replies I start to write.
As Ze Frank put it: I have a theory about this but it's a little bit to deep for the audience.
This is the way.
I was gonna respond to you but actually decided not to.
Don't worry, Reddit/Facebook/Gmail et al. still transmit that draft reply to their servers, store it against your profile, and train on it. Probably.