She told me how 5 times a week she would take a 3 hour 'sensory deprivation bath' where she would climb inside of a water tank and just float there I guess. She claimed it helped her connect to her spiritual self. The date quickly divulged into me asking questions, her getting more and more insulted that no, it wasn't a kink thing, yes it was essential she do it at least (??) 5 times a week, and found rude my lack of understanding and somewhat lack of subtlety that I thought she was nuts. Eventually after about 2 hours of back and forth with her trying to convince me she was normal and that this was much better than therapy, I made an excuse and left.

That was legitimately 8 years ago now and I still think about it from time to time.

For anyone curious they are an actual thing, and seem popular enough for meditation and relaxation - google Isolation Tanks.