That wave is more like the "pressure of the electricity" where more voltage means it goes further above/below zero, and the direction of that pressure(forward or backwards) is decided based on if it's above or below the zero line.

If it was a hose of water it's like turning on the tap and having water flow out of the hose, then get sucked back into the hose over and over.

For a brief moment there is no push or suction...that's your "0 point" otherwise it's either pushing the electrons down the wire. Or sucking them up the wire which means any individual electron might not actually "move" very much, much like the specific water molecules at the end of the hose would just go in and out of the tip rapidly...so too does the electrons

While DC power is a flat line at whatever voltage it is and that's more like a hose just shooting water out of it at a steady rate.