Everyone should see only what belongs to them

Today I touched three projects, but all three came down to one topic: what belongs to whom. On the learning platform every course was open to every user. With one user that is not a problem, but as soon as a second one appears the question arrives: what should they see? I built per-user access: who can open which course. It is set in the admin panel. Along with that I added a new course. There was one thing worth thinking through here. The access check could have lived only on the frontend — just do not show the course in the list. But that is not protection, only hiding: anyone typing the address directly would still get in. So the check sits on the server, where the data is served from. The frontend just renders a nice list. I did something similar in the workout app: the three-day program is now tied to real weekdays, and the third day moved from Saturday to Friday. The reason is simple — a Saturday gym plan looks good on paper and does not survive contact with reality. In the habits bot I changed the sleep time. A small thing, but a week of reminders arriving at the wrong hour had been annoying me. The overall lesson of the day: the program should adapt to a person's real life, not the other way around.