what drives Trump's habit of awful tweets

[paulkienitz]

4. he doesn't care about twitter responses -- probably never reads them

To him, Twitter is a broadcast medium. He takes a response seriously when he sees it on television. If a policy is so unpopular that mainstream TV starts to piss all over it, then he will sometimes actually back down. It's happened like three times already since the inauguration.

Of course, the backing-down may only be temporary.