Why do astronauts on the ISS have a shower problem?

The force of gravity is constantly acting on the surface of the planet. When you open the water in the shower, it is due to this force that the water falls from top to bottom. However, weightlessness acts in space, because of this, the water does not fall down, but rolls into balls and moves in different directions (depending on the acceleration of the spacecraft and other factors). That is why taking a shower is a big problem for astronauts.