It has become a bit of a classic, so here’s president Bush rubbing the shoulders of bundeskanzler Angela Merkel at the G8, last summer.
(for higher quality images, see this slideshow)
This bit of cross-atlantic communication between Bush and Merkel comes fairly close to a cultural misunderstanding.
Yet I do not think Bush’ gesture (giving a shoulder rub) was misinterpreted. I would say that giving a shoulder rub (or quick massage) is a gesture of closeness, saying it is okay to let your guard down. This can be accepted by the receiver, who is then however in a bit of an underdog position. They both seem aware of this.
Merkel, however seems surprised and her response is clearly one of not accepting. Instead of undergoing the shoulder rub and all its implications, she puts her hands up and smiles uneasily. To me this indicates she tries to make a compromise between shrugging him off and letting him save face.