Its difficult to go wrong when starting with a well sorted steel frame
If I could find some of my older pics, I think I did succeed in making some look truly awful 🙂 Bash guards, over sized stems, mismatched rims, often one with a rim brake surface. They all worked though, mostly.
But I agree with you — it would def be hard to make my Soma look bad. I think what I’ve realised over the years is that, at least to my eye, simple, subtle, and symmetric is what gets me. Little things like the stem and bars aligning with the top tube.