Too many to count. Biggest mistake was passing up a MusicMan Cutlass II (Stingray with a graphite neck) in translucent cherry red with a clear pick guard back in 1978. I was a kid who took the bus downtown to the music store just to play it.
I was a sign painter that did a window for a vintage guitar shop. He offered me a 1974 Precision in trade. I took the cash and totally regretted it later.
Other missed opportunities were a used Modulus VJ4, an early 70's jazz, a mint trans. blue G&L2000.
...and to this day I regret selling my '74 Ric 4003.