I have a sweet tooth, so on my last trip, I tried to sample candy from all around the world. I tried an interesting chocolate bar in the UK which had an interesting honeycomb center. In Japan, I tried some marshmallow rice balls which were veeeerry interesting. I also tried some German chocolate. There were some other things as well but I can't remember what they were.
I've done that too! I'm not a foodie or a big drinker, so the table service or "Drinking Around The World" aren't really my thing, but I do enjoy sampling the candy of each nation!
To answer the OPs question, I will echo what everyone else has been saying. In addition to the "major attractions" (the 2 boat rides, 4 travelogue films, and American Adventure) I enjoy the Art Galleries, the live entertainment (I'm partial mainly to the music, but I also loved the Dragon Legend Acrobats in China. I haven't seen their replacement yet), and also just going at a leisurely enough pace to soak in the atmosophere and buy into the illusion that I am really traveling around the world.
So I like to enjoy things like the exterior architecture, which is extremely well done, the music loops, which are among the best in WDW IMO, and the garden areas .I particularly like the gardens in the two Asian countries, the train garden in Germany, and the wilderness area in Canada. I also LOVE the "perpetual night" that is the Mexico interior. I even enjoy strolling through the shops, looking at their interior design as well as their merchandise, which is generally more "authentic" than the typical stores in the parks.
As others have mentioned, I also really enjoy a cruise on the Friendship Boats, especially if I can snag a seat on the outdoor back row, and feel the nice breeze!
Most of this stuff would likely be missed by those trying to cram all of the Epcot attractions into one day.
I know when I started "slowing down" and devoting a full day just to really absorb World Showcase, I started appreciating it more!
Have fun