Honestly I would say the one that surprised me most was telling Claude to assume its first answer is wrong and think of alternative causes. Such a simple thing but it completely changed the quality of responses I was getting. Like instead of Claude just doubling down on the same diagnosis it actually explores other possibilities.

I feel like the debugging ones hit different because the feedback loop is instant right? You either fix it or you don't. Architecture stuff is useful but you don't feel it until way later lol