I even remember running some prank app on my Android that MITM-ed everyone's connections and started slowly removing letters from the website or replaced all th

I even remember running some prank app on my Android that MITM-ed everyone's connections and started slowly removing letters from the website or replaced all the images with cat pictures. It worked super well. That could've have been more than 10-15 years ago. Things have improved significantly with HTTPS adoption.