The word here for "upright" is yashar, and occurs over 100 times in the Bible. From a root meaning "straight" it is translated as with words like just, meet, well, or right. You'll note that I didn't have a Klingon word in this verse - I'd suggest for this text that lugh: be right, correct could make a good choice - for the Psalmist is telling us that when we are "right" with the Lord we can, we should rejoice and praise God.
When I stay on that road, the right path, things around me make sense. I cannot count on earthly rewards, but I CAN see the way things are working - the way they work together.
I play trumpet in a few community bands, and the occasional pit orchestra. One of the things you need to do with a brass instrument is make sure it is oiled properly. It doesn't take too many mistakes to learn that when you take your trumpet valves apart to oil them, they only work RIGHT when I put them together correctly - if I don't get them lined up with the tubing I'll never make any music.