The biggest hack I've ever done was at my school. At my school they gave out MacBook pros for the school year. They had the student account and an admin account on each computer so that there could be restrictions and there were a ton. Well I figured out the admin password which was a super difficult one. I then proceeded to install NMAP. Then I scanned the network for every Mac which was on the network. Since every laptop had an admin account it, I had access into every student computer. I then wrote a script that ssh'd into the admin of an ip I specified, cracked and dumped all passwords of the entire computer into a text file, scp'd the file back to me, turned on screenshare/screen controlling, and then deleted all traces of me ever being there. I did that for months and ran it 24/7. I had everyone's password for every account who went to my school and also could control any computer. I also hacked into a teachers loaner computer which had an admin account on it. I wrote a python wifi phishing script and then got the staff wifi password. Nobody ever figured out. That was when I was last year as a sophomore.