Well, you've come to the right place, for as the great, Salmon smoking Texas_Blues once said, "We're a drinking forum with a pepper problem".
One thing to know about beer when going into it is that it's all made with different ingredients. The basics are Malted Grains (malt) which provide the sugar that is eaten by the yeast, hops (which provide the aroma and bittering components), yeast (which eat the sugar the grains provide and produce alcohol), and water.
The crappy BMC (Bud, Miller, Coors) that your friends drink substitute alot of their grain with Rice halls (cue headache) and very little hops.
Good beer has a decent amount of hops (to the point that you can taste them...hmm...tasting hops, don't get that with Bud), different grain types (which provide different colors and taste), loads of specific yeast (not your general Lager types...which can be quite good btw), and other ingredients too (fruit, oatmeal, coffee, pot, magic mushrooms, potatoes, tea, sake, etc etc). Hell, some are even fermented with Champagne yeast, some are aged for years in oak barrels before release, and some are even...GASP....homebrewed (like mine!)!
You said you like Sam Adams White. Let's start there. I don't like Wit beers (aka White Beers), but of the ones that I've had and not made horrible faces on were Hoegaarden Original White Ale (because it doesn’t have Corriander which is what I hate in Wit’s), Ommegang Witte, Ommegang Witte, Blanche by Weyerbacher brewing Company.
After that, start trying different styles of beer (because, as
this list shows, there are many different kinds and tastes). Who knows, maybe you are a hop head and just don’t know it yet!