Jazz and popular music of today owes a huge debt to Africa where the driving steady rhythm, swing, and accenting beats 2 and 4 come from. Most audiences in the US don’t know this, and don’t feel that kind of beat. Because of this, audiences frequently end up clapping on beats 1 and 3, as they’re doing in the clip below. Harry Connick Jr. knows better, and he also knows how to turn the beat around so he can help the audience clap on 2 and 4 (that happens around the :39 mark in the video below). His drummer is happy about it and gives a double-fist pump right after Connick makes the switch. Notice how much more hip the sound is!