I like riding in the normal railroad caboose. Yes it can be hot and sweaty in there, but in the evening, sometimes you can get the entire car to yourself because most people don't know it's open. Its those kinds of little details I love. They don't need to keep that caboose open for the few people who ride it every day, but they know that the few who do really enjoy it
Also, I think this may win as the smallest detail mentioned on this thread - I love the area music in Tomorrowland. I love how it pays tribute to older rides by including their songs (Miracles From Molecules, Theres a great big beautiful tomorrow). Whenever I'm in Tomorrowland, I sing along with the area music. You should see the look on my friends faces when they see me singing "Miracles, from Molecules are dawning everyday! Discoveries for happiness..."