I have plenty of stuff that I miss, but none I really regret. I overthink every big(and most small) decision I make, so I rarely have any huge regrets on that stuff. What I mis most is my Scrambler project, but I did make the right choice. I wouldn't be as financally comfortable as I am today and wouldn't have been able to buy my dream house a year ago. Sitting on my comfy couch in front of the wood stove in my log house is definitely nicer than working on my $45k over-built Jeep in my parents' garage
You didn't ride the quad anymore, so use the money for some responsible stuff, but use some of it for fun stuff too....stuff you'll actually use.