I currently use TinyWall Firewall, it works very well, it’s small/portable, no complaints I even donated to the Dev but I would really prefer open source, also it needs to be user friendly like TinyWall so my non-tech family members can/will use it like they do with TinyWall.
You can have a preference and not do the preferred thing all the time. In the example you gave, someone could generally eat “healthy food” and just have a Big Mac meal once in a while.