Hand tool woodworking. It's amazing what you can make without a single electron. Its also amazing to feel the tools, the resistance and subtle vibrations as you use them. Like an extension of your own body. I love chiseling, especially large mortises. Hearing that sharp, deep thud, and seeing it sink in as it bites into the wood is so satisfying. Especially when using metal hammers, they are so responsive.
I love sawing, especially when relaxed and working at a slow pace, seeing all the sawdust fly out with each stroke. Sawing isn't fun when working on difficult pieces of wood, when working in a relaxed manner with softwood, the hoarse sounds of the saw starts to sound like purring and it begins to cut exceptionally well.
I love the finish of handplanes, so smooth it becomes water resistant.
Overall very spiritual and relaxing (as relaxing as you allow it to be at least)
Hand tools are spiritual in a way that machine tools will never be. I love the texture and heft of planes. The simplicity and quiet operation. Working with timber and steel is one of the greatest pleasures in life.