I agree most wines are difficult to differentiate. Very rarely, there is one that stands out from the crowd. OTOH, bad wines can be really foul.
Two reds stick out in my memory. One was a Heathcote shiraz which retailed at $400 a bottle. It arrived at the wine lab where I worked. Only 5 mL was used in testing, staff were allowed to take the rest of any bottle home.
The second was a Booth's Premium Shiraz. It only sold from the cellar door, $15 a bottle. Impossible to leave any after the bottle was opened, it had a hypnotic quality.
Booth's was a family business, the patriarch was Cliffy Booth. The secret to making that wine died with him, it was never the same after he passed.