Question is in the title. My life is not as interesting here as many, but I'll answer as an example.

Best: 2013. First child born, Business took off, purchased a new house with a fabulous garage, 1966 Imperial crown purchased. A few very nice trips to Colorado, SoCal, and South Florida... and one fantastic party: Opening of the New Mercedes-Benz store in Wichita. Six figures dropped for this red carpet event. Really a red carpet valet when you pulled up. Actors/models flown in from New York pretending to be Paparazzi with cameras as you walked up the carpet. Open bar and finger food carried by waiters on silver platters. Dance floor with a live band in the service drive and a runway fashion show/technology showcase in the service bay. My 500SL got front row treatment with all the classic/exotic benzes. A night I will never forget.

Worst: 2008. Most of my good friends had the good sense to get out of Wichita while the gettin' was good. I nearly failed/dropped out of college because the foreign language requirement of my major was ruining me. Miserable relationship after a multi-year dry spell making me never want to bother with romance again. A whole lot of effort put forth for a good friend running for office who got clobbered on election day. This turned around for new years when I took Ol' Turbo (1985 300D) on a cross country voyage to California.

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1985 500SL Euro w/ AMG bits 130k
1984 300SD Turbodiesel 192k
1980 240D Stick China 188k
2001 CLK55 AMG 101k
2007 S600 Biturbo 149k Overheated Project, IT'S ALIVE!!!