I made my largest gains in programming competence almost
10 years ago when working on a system with no connection to the internet and no cell phone at hand. I was working a development assignment on an air-gapped network. Not being able to search google every time I got stuck forced me to actually read the documentation, man pages, and reference books and think through what was going on and come up with solutions. The internet terminal was a 10 minute walk away so I treated it like a trip to the library for research only after I had spent time working on the problem myself.