Poor decision making, for the most part. ;)
A good friend brought up Newgrounds and more or less pushed me into registering here, so medals I had earned would show to them. Leading to me making an account and re-playing games I had already finished. Then I came across a user's list of medal games that were worth the time investment. (That was so far back, I think I actually still used Google search back then.) At some point, aforementioned friend quit medal collecting and I kept going, discovering a (now defunct) 3rd party tracking site for medal score, user levels, etc. which got me interested in exploring how far I could get.
Fast forward to a few years back when I stopped logging into NG entirely, because I had stopped caring about medals (mostly because there was no quality control anymore for which games could get medals). I had less and less time for games in general, so I didn't want to spend that time by chasing medals.
While I had always had an interest in art and animation as well, NG became associated with all those crappy medal games I had sunk way too much time into. A mix of the bitter taste of having "wasted" that much time and never wanting to experience "medal-FOMO" again kept me away for... "around a decade" I'd say.
What brought me back to NG in July(?) of 2023 was actually the NSFW content that "certain users" love to bitch and moan about. After a while, I decided to stay with this community again and help it out where I saw good opportunities to do so. (Which is a nice way of saying: "How can y'all be so bad at things that 'I' am able to help you...?" ;p )
JME10135
Well, it just happened. First I only wanted medals for certain games I found were worth it but then I started to try to get as many medals as possible and that is basically where I am today.
Andrey20 (Updated )
Thanks to JME, for sharing your story about the medals. Your gaming skills are above mine :)