Softened water feels slimy to me - similar to seawater.

I actually do have a whole-house softener which came with my house. I installed a bypass valve so it does not feed the pipes in my home.

It may be over-softening. Our water felt slimy until we replaced our old unit. The new unit uses way less salt (at least 10x less) and the water feels normal.

I believe the old ones had an adjustment, but I can confirm new units definitely do. We hardly use any salt at all.

It's easier to rinse soap off with hard water.