This is my interpretation of this Original Post. I am interpreting it and writing it again so that it makes a mark in my mind.
1. Why is it important to do a thing really, really well?
By focusing all your resources at one task, you will be able to do it much better than anyone pursuing the task partially. You will find ways to automate processes, to get done more. You will be able to deliver more value.
Also doing one thing really, really well will establish you as the leader. Who doesn’t want to be associated with a leader?
2. Why the really, really ?
It stresses on being the number one in that “thing”. People always recognize the number one. For example very few people remember who came second in the last soccer world cup. People always remember who won it. The winner gets 95% of media coverage rather than getting 50%. Thus being a topper in what ever you do is really important. Coming second should not be an option. That’s why do a thing really, really well.
3. What mistake do people make while adopting this philosophy?
The first task here is to find out what is the “one thing” which you do really, really well. If you can answer this question, then doing “that thing” would be the path to follow. However people often try doing things they are not good at. This doesn’t make sense. Ask yourself, “What am I good at?”. “What is that one thing, I can do really, really well?”. Don’t dive into something that seems do-able or hot.