What makes a good scientist? In my view, intellectual curiosity, attention to detail and perseverance are indispensable qualities in the practice of good science. No less estimable a figure than Thomas Edison sums up the value of perseverance thusly(make of these quotes what you will; I take them in the spirit in which they were given):
The above link contains Edison’s thoughts on curiosity, observation and social progress.
A recent experience of my own reinforces these characteristics:
I was writing some Python code and was suspicious of my results. I tested the code within my Mac OSX Terminal app (I frequently do this) and received a different answer. Please see screenshot below.