If you have an account in the trueachievements website, they have created nice page for all their users about their gaming decade... 10 years of gaming displayed in one page.
I checked out my page and it is quite interesting stuff ...
my Fastest completion - Microsoft Mahjong - 16 minutes
How did that happen? I know that I have played this on Windows phone, Windows 8 and and Windows 10 at different times. All of them have different achievements, but somewhat centrally stored statistics about user profile. When checked their site, I see Win 8 had only 3 achievements worth 25 GS that were easy to obtain. Basically they were Play a game, play game in Hard difficulty and Change theme. No wonder it only took 16 minutes to complete.
my Rarest completion - Crossout, 300 days, completed by 248 people
This game only had 13 achievements, but it was hard to complete - the last one "complete 10 Leviathan raids" was tough for me as I was mostly solo player... when attempted the Leviathan raids - usually the matchmaking failed because there were not enough players in the queue, or I was teamed up with random low level players who had no idea what to do, and had very low level gear... so no chance of beating the Leviathan. Even with skilled players, the raids failed many times.
my Slowest completion - Sid Meier Civ Revolution - 2040 days... TWO THOUSAND and FORTY DAYS!!!!!
Looking at the stats, I see I started playing it in June 2008 when I got the first achievement. Then played it over period of time. Got "won as Mongolian civilization" achievement in November 2008. Then who-knows-what happened and the game was shelved and forgotten for years ... next achievement I got only in 17th January 2014 and then grinded through the whole game and all remaining achievements in just 2 days :)
Completed games - 45 - 31.57%
I can also clearly see that the time I was between two nine-2-five jobs. I was unemployed and did short roles and some months here and there contracting - I did much more gaming and got more GS than when I was employed full time.
My personal stats page can be seen at https://www.trueachievements.com/decade/365872