You might be surprised to find that for many interstate routes, there are non-interstate routes (in full, or in part) that offer significantly greater sight-seeing opportunity and aesthetic quality for little extra time.

You might also be surprised to plug in seemingly out-of-the-way mid-points in the automatically generated route, and find that Google is not choosing the fastest route for you, or even the shortest.

If speed isn't the primary consideration, then seek and consider alternate routes. If speed is the primary consideration, consider changing your plans and priorities.