All of them have obtained a unique motivation for learning more science and technology, some will start a career in space research. Throughout nearly 40 years of manned space flight, only relatively few of us astronauts and cosmonauts have been privileged enough and have been lucky enough to experience the weightlessness in space.
Weightlessness is very different from Earth.
Not only do we need our legs to move, but also all things on a table stay where they are because of gravity. Gravity is so fundamentally intertwined with everything around us and inside us, it goes deeply into basis processes of life and production of goods, e.g. biological processes on cellular level, production of high quality alloys etc. That is the reason why being able to study these processes in weightless is so exciting and valuable. Only by making experiments in weightlessness, we can learn about the influence gravity has on Earth. Space research is a prerequisite for our survival, we need to learn how dependent we are from our Earth, we need to look beyond our present horizon.