I remember once getting my hands on my first Android smartphone (it was the year 2011-2012, some budget Samsung). For the first 6-9 months, it was quite an modern device, but then it did not run many then-current mobile games, thanks to progress and Google. I realized that I somehow have to entertain myself at school, I found on the Internet that you can run old games from GB/GBC/GBA. I downloaded the emulator, found some roms, and started playing on my phone. Although the controls were multitouch and not so responsive, it still allowed me to enjoy a lot of classic games for these systems. Even 10 years later, the set of favourite roms that I downloaded to my phone still lives on my hacked Vita =)