I've met maybe 1-2 people in my whole life who were clearly beneficial 'A' from the get go. There's also a weird 'A' that tries very hard but causes more pain than inspiration. Meaning, they're clearly smart but think that's all that's necessary to be useful. I once worked with an intern from MIT who came in and immediately submitted large PRs everyday that improved the algorithmic complexity for a bunch of functions…
I can think of two reasons why he worked that way:
1. It was unclear exactly what he should be focussing on. Were there tasks/tickets describing what needed to be done? Or was it just a vague “fix this”. Doing peephole, local changes to code are easier and improve understanding of the whole. 2. In addition to working on the main tasks, I tend to fiddle around with other code while the main problem is percolating in my brain. Somehow working on other problems helps me solve my main problem faster than just focussing on the main goal.