I can go with either extreme or anything in the middle, depending on what fits the story, tone and aesthetic.

At the same time, either one can look stupid when there's no thought put into it. We don't necessarily need to know how any futuristic stuff works, but it helps if the people designing it have some vague idea of why things are there and what they are supposed to do. It doesn't have to be realistic, but it can help it stay internally consistent. And it helps avoid the pitfalls of lazy or obviously impractical designs that can plague sci-fi. It can be very distracting when the set is a bunch of random plastic tubes, half the contents of a Spencer's Gifts, and recycled props that have been bouncing around for decades despite having no apparent function.