That's exactly why Johnson he did it; to invade your personal space...LBJ wouldn't have been as effective in Europe where people's personal space is much smaller...
But, love 'em or hate 'em, the "Johnson Treatment" was effective.
Newspaper columnist Mary McGrory described it as "an incredible, potent mixture of persuasion, badgering, flattery, threats, reminders of past favors and future advantages"; Washington Post editor Ben Bradlee recalled feeling that "a St. Bernard had licked your face for an hour, [and] had pawed you all over"; and Hubert Humphrey described it as a "tidal wave."
http://face2face.si.edu/my_weblog/2009/05/lyndon-johnson-and-the-johnson-treatment.html
BUT, he knew his place...