I can think of quite a few almost right away.
2003 - Even though I had started collecting Bionicle sets since they first came out in 2001, that was the year when I really started getting interested in the storyline, and it was not yet too late to really experience all of the earliest online content (2004 was pretty much the first time some old content had been removed from the Bionicle website, so I was fortunate I had the opportunity to see it all while it was still up).
2006 - My personal favorite year of Bionicle content of all time, from the new characters featured in the sets (the villains being an actual team of individuals with their own personalities rather than just swarms of mindless minions, and the heroes being a group of familiar names since the beginning now getting a chance to really shine), to all of the various games that were made for that year (both online Flash games and the console/PC game "Bionicle Heroes" which I played through full completion over a dozen times), pretty much the only thing that could've made that year better for me would be if another Bionicle movie had been made like in the three previous years. Also, that was the year before the first iPhone came out, and I never owned one until ten years later, so for much of that ten year period, I often liked to say that my familiarity with technology was stuck in 2006 (essentially admitting that I was behind the times, not unlike how I never had an email address until 2007).
2008 - My first full year as a member here on GoF, when I grew to enjoy this wonderful community, as well as started writing and posting my very first serious effort at writing fanfiction.
2013 - Pretty much the peak year of my activity on GoF, when I ended up winning the Appreciated Member award in this site's annual awards voting, a lot of certain members I was particularly fond of were still active, and was when I posted what would ultimately turn out to be the final chapter of my first fanfiction project for which I would later end up cancelling any further progress. It was also in that year when I first gained significant interest in the My Little Pony fandom and had a fortunate opportunity to get fully caught up with the ongoing series just before the start of Season 4.
2014 - The Lego Movie came out (still one of my favorite movies of all time) along with the video game based on it (which I played almost as much as Bionicle Heroes, and would ultimately inspire me to consider trying all the other Lego video games as well). In was also in that year when I began writing and completed the first of what would later turn out to be a massive series of fanfictions that I'm still progressing through to this day.
2018-2020 - It was in these years that I set out with the goal to complete every single Lego video game I could obtain. At the very start, I had a feeling it would take me three years to accomplish that, and it turned out I was absolutely correct. In fact, in hindsight, I believe those particular years were the perfect time to do that, mainly because it has now been just over two years since the most recently released Lego game, by far the longest gap between releases ever and still counting. (I was unwilling to pay full prices for those games, not to mention I might've had difficulty completing some of those games if not for some helpful guides made by other players. Had I tried to start this effort just one year earlier, I would've ended up feeling compelled to pay up for the most recent games less than a year after they came out. And with how crazy things have been so far this year for me in terms of just trying to get stuff done, I don't want to imagine how much worse it could've been if I tried progressing through all those games on top of everything else, had I started this effort just one year later.)
