Ask HN: What are some of the pain points of making hardware products?

Recently there has been several posts regarding hardware being hard. Such as a hacker news link on this: https://medium.com/bolt-blog/will-your-hardware-startup-make-money-677a8e6c665b Probably due to the latest batch of YC having an increase in hardware companies? Who knows. In any case, for anyone who has made hardware products before (crowfunded or not, both), what are some pain points that are so stupid and irrational, you wonder why it hasn't been automated yet? Please share your stories!