I had LOTS before I had one from a friend who really knows wines.

That changed my opinion of champagne as a whole, but most of it (especially in the US, or the Brut style) just sucks.

But that's wine in general. I've had lots of mediocre wine and a few that were fantastic (to my tastes).

Consider all the varieties and vintages, then everyone's personal tastes, and it's no wonder opinions are all over the map.