From my limited, albeit long experience, I've found that there is a wide variety in the different wine varietals.
You have to look at more than just the varietal. I've found a wide variety within each one, and a lot depends on the AVA, the winemaker, the vineyard, etc.
You can't poo-poo one entire varietal, based on one or two wines. I've had some wonderful wines (PS, CS, Merlot, SB, etc.) and I've had some horrible ones (PS, CS, Merlot, SB, etc.).
There is a lot that depends on the winery, the winemaker, and the vineyard. You can have great grapes, but you could end up with vinegar if the winemaker (or assistant) goofs up. There's science, but also some artistry by the winemaker in producing fine wine.
The other thing to note is that while you may not like certain varietals, someone else may love them. That's what is so great about this community on Wine.Woot ... if you don't like something, there's always someone willing to buy or trade it with you because they like it.
And that's my
But as TheMostRighteous always puts it ... YMMCV!