During the various sub-projects of my PhD (physics) we encountered several difficulties (as it is common, I assume) both in technical and in physical nature which we had to solve. Moreover, some experiments resulted in bad results or no results at all. Nevertheless, we identified the issues and noted how to avoid those problems (or how to fix them) in the future.
After we spent considerable time investigating and fixing those problems I would like to mention those issues (and the solutions) if not in papers, but at least in my thesis to avoid future readers the same problems, but my supervisor is completely against reporting any negative results. His stance is that any negative result or technical issue would paint me in a bad light (even though we could solve them), and therefore I only should report good results without mentioning problems.
This confused me (why would anyone view me in a negative way if I report problems in my thesis, and how we could circumvent or fix them), and my local colleagues could not give a conclusive answer either. Therefore, are such stances common, and if yes, why?