Red wine should be aerated, i.e., allowed to breath.  You can buy a simple aerator that will do the job, twirl the wine in the glass, or just let the wine sit for  awhile before drinking.  Of course, if the room is warm, see above....
One question you may be asking yourself:  why should I buy wine from a winery rather than Cosco, a supermarket, or a wine shop?  Well, for one thing, if you visit the winery you taste the wine before you buy it.  Then there is the fact that Cosco and the supermarkets don't store the wine properly, so even if you get a good wine the first time the next bottle you buy might not be as good.  That assumes they still carry it and you can remember what it was you bought in the first place.
But there is another reason -- wineries in Southern California make varietals that you are unlikely to find at Costco or a supermarket.  I list  a whole batch of white and red varietals I've tasted at the wineries I've reviewed.  Costco only carries around 15 red varietals.  You won't find two of my favorite wines:  LaGrein and Montipulciano.  To make it easier to find a winery offering your favorite varietal, the wine varietal wine lists are now in the Wineries section (just above the pictures of the bottles).