You have a Belgian beer bar?!? I am jealous we have tons of "Irish pubs" and thankfully one that serves some good variety but that's it.
It took me many years to get brave enough to branch out from the basics but even with that my taste is very specific. I'll try anything once and either I'll get it again or not. I personally can't stand guinness but my friends all love it I've tried it a handful of times and still haven't changed that opinion. Probably never will.
2 points your post brings up. 1) People who don't like guinness write off stout, such a shame because there are some amazing stouts out there that make you realise guinness is to great stouts (seirra nevada does a decent one, Black Isle Oatmeal Stout (scottish), Redchurch Hoxton Stout (English)) as carling is to say Pilsner Urquell or St Mungos (or a good lager or pilsner)
2) Interest creates enjoyment and enjoyment creates interest. I find I can't really enjoy/appreciate anything (film, band, music style, book, BEER) unless I know about it, how its brewed, where it's from, what are the ingredients, what was the brewer trying to achieve, what ought I be tasting, where is it in keeping with a style, deviating from a style.
I find if I am helped to understand these things, I can enjoy anything! It's really important to keep an open mind of course, but I find that the whole 'blind' tasting thing can be a bit overrated. Taste has a significant psychological component so i say embrace that element and psychologically prime yourself as best as is possible, and most of the time, your taste buds will be more open and receptive!
PS yes the belgian beer bar is awesome, never seen one outside Benelux and in Glasgow Scotland of all places?!!