That too. However most of us tend to be overtly optimistic about the possibility that something will work as expected. Also we tend to forget the secondary tas

That too. However most of us tend to be overtly optimistic about the possibility that something will work as expected. Also we tend to forget the secondary tasks involved[3]. Also the fact that there is usually an expected schedule/due-date that are presented before being asked for estimates, people tend to invariably try to fit the effort-estimate into the pre-determined schedule subconsciously neglecting the secondary tasks. Its like when asked if i can cook a turkey-dinner in 2hours, i say - "looks do-able, i can try...". Completely forgetting the fact that i am being expected to raise it from an egg, and take care of it for a few months first. [3] Slide 8 - https://www.slideshare.net/cvs26/effort-estimation-73647698/8 https://www.slideshare.net/cvs26/effort-estimation-73647698/...