Earlier quoted context omitted.
Information density can be very overwhelming and a factor for stress. Often a lower density is totally enough and less stressful to use. Providing an optional "compact mode" for people with smaller screens or who prefer denser layouts would be my way to go.
I’m interested to know where this idea comes from. Is there a good reference you recommend? My anecdotal experience has been that low density websites like Medium are more stressful than higher density websites like Substack/HN because I have to do more work to read the text on the page.
There's something psychological about the appearance of a low-density display as well. I can't quite explain it, but it causes me a bit of displeasure because it feels wasteful. There are so many pixels available but they aren't doing anything for me. I don't know why this causes me discomfort, but it does.
Finally, it's important for an application like a mail client to not lose sight of the fact that the way people use email varies. I personally use dozens of folders, meaning the density of the folder list should be as compact as reasonably possible so that I don't need to scroll.