What's the best hand you've never had and ever had?

For me it's the big momma, the royal flush, I have had it once in an all in or fold and that was made by 4 cards on the river so I don't count it.

I've had a couple of straight flushes which are the next best tier, so the best I've had. Had quads of all kinds from deuces to ace's; think I even lost with them to a 9 through King straight flush once 😘

So what's your "missing link"?