[ambulancechaser]

Why? How should we decide to spend the resources it orbit Neptune? Why not Saturn or Jupiter; why not land on a comet? Why not put a human on the moon again or perhaps spend the money or medical research or nuclear fusion. What about Neptune seems so compelling to you? I would never have thought it an important or memorable goal and just want to hear why Neptune is so alluring.

[trentnix]

Because the 10-year-old me was teased with pictures and mysteries I want answers to. Because it’s so far. Because it can’t see more than a pale dot in my telescope. Because it’s so alien. And because we have been there, done that on everything you mentioned.

Perhaps if I’m ever granted the opportunity to present my case before NASA and Congress, I might offer a more well-thought-out explanation. But right now, “because it would be awesome” should suffice.

[Rebelgecko]

Check out the recently proposed Trident mission, and I guess write your congressperson while you're at it

[exmadscientist]

Because it's a mostly unexplored corner of our solar system. The Voyagers were survey probes: they saw glimpses of a lot of interesting things, but couldn't stick around and solve any of the hard mysteries. (For example, just what is going on with the weather on both Uranus and Neptune? It's weird!) Orbiters such as Galileo, Juno, and Cassini are able to stick around long enough to do deep science.

Orbiters for one or both of our ice giants ought to be much higher on our space exploration priority lists than they seem to be.