how often do you type out a response and abandon it?

[Wynton]

A few times recently, I noticed myself typing out replies in threads only to decide half-way through that: (1) I had nothing worth adding; or (2) I did not want any part of the thread.

Anyone else do this much?

One extra question: how often to you respond rashly and quickly regret it? (cue obvious joke about responding to this post)