I am always fascinated by smart people. You get to learn so much from them, it makes work life so much enjoyable.
I have been fortunate enough to work with the best of people in a decade long career. While I landed at Trilogy by chance (I haven't had heard about it before, being the dot com burst era nobody else was really hiring at that time), I had the opportunity to choose my people at my startup. I think we have done a good job - everybody has been awesome.
Observing Top performers out of smart people is fascinating too. At both places, I found some unique qualities in the Top performers:
Talent
Some people are good at what they do - it's like they are born to do those things. They have a natural talent to succeed at their job. Think of people like Sachin Tendulkar, Roger Federer and Michael Schumacher. They are quick learners. Having the right abilities definitely is an advantage.
Motivation
People do unbelievable things when motivation level is high. They convert pain to pleasure to achieve their goals. I have found motivated people do better than the ones having natural talent - they work harder. Talent is meaningless without motivation.
Preparedness
Despite being talented and motivated, many people fail to deliver because they are not following the right "process". Somehow, the mental setup is not right, they just aren't ready.
Talent and motivation take you to only upto certain level. I have seen perfectly capable people underperform when the going gets tough, or when there are just too many different things, or it's a completely new situation. Ability to manage your time, prioritize your tasks, handle context switching, adaption, not burn out are equally valuable skills - the so called mental strength. Top performers deliver day after day. I believe this is the most important quality to be successful - the difference between a Tendulkar and a Sehwag.