What happens if you take two knots, attach a band, and refuse to think too hard? Sometimes you get a new knot. Sometimes you get more knots. Sometimes you accidentally wander into four dimensions.Of course, one might want to think harder and ask why knots are band summed in the first place. In this talk, we think about 4-manifolds (and things inside them) through bands: how knot genus behaves, how ribbon disks can be drawn, and why band sums are yoga exercises for 4-manifolds. The emphasis is on pictures, small examples, and intuition—proofs strictly optional.