A the memories
My very first phone was a good old Nokia 3310. The archetype brick-phone. The ringtone I started out using was "Hurdy-Gurdy", but this wasn't always easily audible so I switched to Sunny Walks. Somehow that little monotone tune is guaranteed to penetrate 3 feet of concrete in a way that makes it still distinctive enough to let you know you're getting a call. To this day even on my new smartphones I have the ringtone set to a MP3 version of the original 3310 Sunny Walks. I've developed an almost Pavlovian response to it now where hearing it will lead to a compulsive reaction to check my phone. It helps I never give my number to anyone that would call me "just because", thus if I get called it's probably something I should answer.