Russians have done things NASA would not dream of. For instance, light a match and see how the flame behaves, inside the cabin where the crew lives and not in a confined box. They've let chicks free, or salamanders, inside the inhabited area...No big deal!

What weightlessness does to habitats like that is very puzzling to even warned astronauts: you use a pen, then leave it hanging 30 cm in front of your eyes while those eyes are distracted by something else, the head moves a little and that movement is enough to cause a slight draft which rotates the pen and when the eyes look for the pen again, they can't find it simply because the pen has changed its position and the brain can't immediately recognize the pen.
Every small object gets lost if not tracked all the time...
But large objects (dishwasher sized or more) are a lot easier to move!

One day, perhaps, we'll see a spacesuited astronaut grab a manned spaceship with his feet locked to a space station (or a crane) and slowly move it to a docking hatch on the station!