Happens all the time.
The trick is to learn how to assess the best thing to do -- switch the original plan to something totally different, tweak it just a bit, or go ahead and finish it trusting that you will like it when done. My most recent experience was the Gravity quilt blocks I made. The individual blocks are beautiful but I just wasn't loving the effect of them all put together as in the pattern. My solution was to break it up into several smaller projects -- 2 table runners, a wall quilt, and 2 smaller quilts. I'm happier with how the blocks look, I'm using what was an investment in time and materials, but I'm not spending a huge amount of additional time doing the finishing and quilting on a very large quilt that just doesn't quite work for me.
With the WIP you posted, I think it will all come together with some great quilting -- lots of space to create some texture and subtle pattern from whatever type of quilting you decide to do. Finish it up, set it aside for a while, and them come back and see how you feel about it. If you don't love it, post photos on social media and whichever friends seem to like it best get a nice Christmas or birthday gift. I guarantee that someone will find it works perfectly for their modern/ midcentury modern space.