Could you give an example or two of something concrete that you don't think is sufficiently addressed by today's operating systems? In my day job I do data eng

Could you give an example or two of something concrete that you don't think is sufficiently addressed by today's operating systems? In my day job I do data engineering, and I'm a long-time linux user. Multimedia stuff aside, I think it's been 8 years since last time I felt limited by the operating system. Granted, I don't do anything particularly low-level. But as a high-level "consumer", I experience the main issues with today's operating systems not to be technical capabilities, but rather user friendliness, flexibility, and standardised APIs. But I'm curious what the issues are from a lower-level point of view!