a tip for the fifteen year old self, don't take this advice just be aware of it so you know what technology to invest in
This one is awesome advice! I remember the discussions with my dad. I told him there's no other way than to compile your own operating system from scratch. How could you ever not do that? I was trying out LFS and gentoo at the time and loved it! He worked on business critical software on IBM mainframes.
I wouldn't be where I am today and wouldn't know what I know today if I hadn't done what I did at the time. Installing an LFS system teaches you a tremendous amount about how your operating system actually works (if you don't just blindly copy and paste stuff and give up if something fails). I created `ebuilds` for my favourite software at the time that wasn't part of gentoo yet. I learned a lot from compiling software with my own optimization combinations, including some things that recently went by here on HN (-O2 and -O3 are way different and while one may make things faster it can also horribly break software). I'm not a C developer and I no longer do sys/network admin work but I do like to think that it gave me a great foundation and it definitely has helped me in more than one job to be the "bridge" between the devs and the sys admins. I spoke both languages. When other devs just complained about the "unreasonable requests" the admins had for them I understood why they made those requests. I also understood the dev side though. I could translate between the two.
Nowadays? I cringe at recompiling my operating system. I just want to `apt-get install` and be done with it already from one LTS release to the next because nothing is worse than having the "TV" out of commission for longer than the couple hours it takes to download and do all the upgrades. I don't have time for this (as you can guess, my TV is a Linux box hooked up to the biggest monitor I could find for the kind of money I wanted to spend. There's not ever gonna be a "Smart TV" in my house, not over my dead body). I have kids that need their Netflix running!