Not sure if these count but it was Killian's Red and Bass Ale. After that, I upgraded that same Summer to Weihenstephaner and haven't looked back since. (mid-1990's)
Easy answer: Sierra Nevada Pale Ale. That's my Budweiser. But maybe more to the point of the question ... I became a Beer Nerd because I went to a Where's Waldo (now: Waldo's Special Ale) event in 2014(?) and it was unlike any other beer I'd ever had. Yes, it was boozy, but it also had crazy flavors that were dank and earthy and delicious. It was the first time where I realized there was so much to beer that I had not explored and made me the person I am today. Sadly, subsequent Waldo's expressions haven't lived up to that memory, but in Lagunitas' catalog, I do quite often enjoy Born Yesterday, particularly day one - although that's not really a thing these days.
Dogfishhead 60 minute was huge when I first started craft beer. For me it would have to be harpoon ipa or nebco gandhi bot, when they had gandhi as a robot on the logo. Also shout out to nebco imperial stout trooper. The one with a storm trooper wearing sun glasses
Art Car IPA,just a few months ago actually. I am 50 and up to that point I thought all beer tasted like Budweiser.
I'd think that most people would consider 111 years old "real old" but until I get up in the 3 digit area, I'll hold off commenting.
Unibroue Blanche de Chambly in about 2006. Stumbled on it in a Food World in Northport, AL. At that time craft beer didn’t really exist in the state so I didn’t even know what it was.
It was the first IPA to label itself West Coast. Russian River and Stone were around for a while before Green Flash started up.
Edmund Fitzgerald porter from Great Lakes Brewing. I find it WAY too hoppy these days, but at the time, it was the first beer I tjought had a bold, memorable flavor. That was about 15 years ago (maybe a few more).