That instant was unique for human-tech interaction. Perhaps comparable with becoming positively viral, but at small scale.

I remember installing Mandrake Linux on my PC (via CD ordered online as magazines still hadn't started to include the CDs). I had the dial-up line and the modem but didn't know how to set it up as I was new to both Linux and dial-up. So I used to print the steps from websites/mail groups at office to try them at home. Initially I couldn't make it work and had no choice but to wait to get to office the next day to start again.

Finally I read a bunch of docs about how to talk to the modem and eventually I managed to do the correct steps and the modem produced its sweet handshake tone and the indicator lights started to blink - it was such a pure joy to finally be online from Linux!

The opposite, connections that drop or slow down, the sound of music that is buffering or got automatically downgraded to the worst available quality.

Not sound, but visual: The moment the video stream goes from blurry to crisp.

There is still a lot of emblematic sounds, the skype calling sound, netflix loud bang bang, the iMessage or messenger notification pop sound, etc.

But there are all from company sound design and the same experience as the dial up sound.