I only take medicine when the symptoms literally prevent me from functioning or threaten my life. With fever, I actually wrap myself up to keep warm, which lets my body "rest" instead of working to raise my temperature. This approach appears to have helped me get through many infections quickly, though I admit this is anecdotal.
Depends on a lot of things. If medicine like paracetamol can make you suffer less with little to no downsides, there's no reason to avoid it. But other than that, I'm also in the same camp of letting the body do its work. Definitely things like antibiotics are more trouble than they're worth in most cases.
I think that's a fine decision to make, as an adult, for benign things.
People who make that decision for their child, for more severe stuff are pretty wack though.