Nursing would be among the worst professions for me. It requires a lot of simultaneous attention to wide variety of details - the cost of missing something is somebody's pain, injury, life... I can focus really deep on one thing at a time - suited me well in Math before and in programming now - while any situation requiring attention to a several different details in parallel or quick sequence just exhausts me.
Related to it is the perfection level required. Take the simplest thing - inserting needle into a vein. Doing it a 1000 times, you need to do it perfectly a 1000 times. In my mentality - it is much more efficient/faster to do something not perfectly, thus getting it right, say, 9 times out of 10 and apply additional effort to correct the 1 out of 10 mistake. The same about following a multi-item checklist (or multi-step procedures) - i immediately filter out "unnecessary/unimportant" items. Obviously, such mentality have no place in nursing :)