It is kind of funny looking at films you watched as a kid as an adult. I remember watching Empire Strikes Back as a kid being kind of a stressful event. Every time I watched that movie I'd squirm the whole way through. There is so much going on, and throughout the whole film you swing from one danger to another and it hardly ever lets us. I remember the part with Yoda acting all goofy being a nice moment to take a breath and have a little laugh.
One of my friends excitedly bought Star Wars when it was first released on DVD so his young daughters could watch it, I think the oldest of them was about eight or nine at the time. Before starting A New Hope, he warned them before hand that it was kind of scary at parts (he recalled his younger brother running out of the theater with tears in his eyes during Vader's first appearance on the Tantive IV back in '77). After the film was finished, he asked them, "Did you like the movie? You didn't get scared did you?" only to receive the response, "Dad, that movie wasn't scary at all! It was actually kind of lame." Needless to say, they never watched the other two movies and he was slightly heartbroken about the whole thing.
I guess kids are so used to seeing stuff like this now, it doesn't come off anywhere near the way it did to many of us when we first saw these movies.