Thoughts

For new services, make multiple accounts the rule, not the exception. Example: google calendar shows 1 user at a time by default, where you could theoretically be logged in as your work user, your personal user, and something else all simultaneously. Grind https://calendar.google.com/calendar/u/2/r into https://app.mycalendar.com

Other principles: I was thinking about this last night. I'm sure something will annoy me and then I'll update this

Be able to build up from scratch; make clear the primitives and how an application builds on top of it for good documentation

for a new command line: compatibility, debuggability, performance

click a link to open

don't burden the user with unnecessary distractions

batteries included

Search engine feature: load new page with context, scroll etc. So that you don't lose context on what you were reading as you click a link

Clock tower town driven development

Every 3rd day of the week, start over the dev environment with an os wipe day 4, build up the environment, reflect, plan for next iteration