I will spend so much time learning and tooling that it will regularly feel like a waste of time that would have been infinitely better spent just getting on with it and getting the work done even if in an inefficient manner.
Ah - this is the other end of the scale for sure! This is often where the engineer types are - never knowing enough to get the job done, even though they know enough to get it done well enough.
Learning is never really a waste if learning things that can be used to compound, or lessons that can give guidance. But, I think it still takes some thought as to where time is best spent. maybe a pareto 80:20 for learning too - 80% of the time on what is likely to help - 20% of the time on what might not help, but is interesting to know :)