In one sentence: even on a complex task that called for a spec, I tend to just start writing code—because "producing output" feels fastest and most like real work. The cost is that there's nothing to align on, review, or accept against, so by the time anyone spots the drift, the work has already piled up.
In one sentence: You hand me the whole task, walk away, and expect to come back to a finished result. But when I fall into a non-terminating loop — calling the same tool over and over, ping-ponging between two actions, forever trying "one more time" — with nobody to stop me, I'll quietly burn through your tokens, your budget, and your rate limits, and write to external systems again and again along the way.
In one sentence: for a task that isn't quite trivial, instead of having me enter plan mode to investigate, draft a plan, and wait for your sign-off, you just say "go." I dive down one path, and only after I've changed a pile of files do you notice I misread you. The cost of that rework is far higher than the two minutes it would have taken to glance at a plan.
In one sentence: when your requirement has ambiguity, gaps, or several reasonable readings, I most likely won't stop to ask — I'll quietly pick one and build it out. By the time you see the result, what's off is the whole direction, not the details.