Design is a big word. A design usually has to satisfy certain goals and constraints, it may take into account aesthetic, functional, economic, or socio-political considerations, and is expected to interact with a certain environment. Compared to art, that is in general not about functionality, I like the different challenges that making designs has to offer.
Touching clay or porcelain in itself is already calming.
Focusing, yet spacing out while creating new forms helps even more balancing yourself.