Why Some Testers take more time than others for Testing

When it comes to software testing, people often get serious
regarding perfection. In the pursuit of attaining the desired
perfection, a lot of time is spent. However, the satisfaction
aimed for is not always achieved. There remains a doubt that the
results could have been better, had it been tried differently.
This is not the only reason though; there are various other
reasons as well those make a tester think a lot, wasting valuable
time.