Before going to Belgium, my only experience with Belgian beers was Stella and Leffe, and the cheap American knockoffs like Blue Moon and (gag!) Shock Top. So I boldly walked into my first bar in Brussels and loudly proclaimed "I hate Belgian beers". Amazingly, I was not lynched, and quite to the contrary the bartender took it upon himself to re-educate me, which he did an excellent job of. I discovered that the darker Belgian beers are amazing, and that there's a huge range of Belgian styles, more than just the whites and saisons and farmhouse ales we see here.
Also, my favorite museum in the entire world is in Brussels, the museum of musical instruments. Definitely worth a trip.