I don't remember the exact year but it must have been 2000 or 2001 when I enrolled in a Pokemon bowling tournament as a kid. The bowling alley had a Dreamcast at the front desk that anyone could play with Sonic Adventure running on it. I stepped up and played the Emerald Coast level and was hooked immediately. I had played Sonic games on the Genesis growing up but this was the first real Sonic game (unless you count Sonic R on the PC) that I had played.
From that moment I knew I needed to get a Dreamcast. I got one used at a local game store a few months later. And here we are today, I'm still playing my DC.