U.S. citizens should exercise caution when congregating in areas known as expatriate hangouts such as restaurants, bars, and discos frequented by high numbers of resident U.S. citizens and/or U.S. citizen tourists. In addition, hooligans, most often drunken “skinheads,” have been known to harass or even attack people whom they believe to be foreigners or members of rival groups. On occasion, German police reported assaults which appeared to have been motivated by racial reasons, and U.S. citizens have reported that they were assaulted for racial reasons or because they appeared “foreign.”
(reisewarnung auf travel.state.gov)
This phantom limb is used as a way of signaling busyness and unapproachability to strangers while existing as an addictive force that promotes the splitting of attention between those who are physically with you and those who are not.