If you are good at everything, you are good for nothing

Candidate 1: "I'm a Ruby on Rails expert"

Candidate 2: "My confidence lies in PHP"

Candidate 3: "I'm specialized in Infra"

Candidate 4: "I can do all the things that the other 3 can."

All recruitment quotas aside, recruiters tend to choose master of one than jack of all trades.

1. Some people think that they are master of all, and they act all high-and-mighty. But digging deep into a certain field, it turns out they know nothing. 

2.The 10,000 hours rule shows that in order to become an expert of one field, you must spend at least 10,000 hours to study about it. If each day you spend strictly 2 hours to study, only after 1.5 year can you be considered an expert in the field.

Not to mention, to master something, the time spent must quadruple or more. Few can be excellent at all fields, but if you stay focused and try your best, you can become the guru. 

3. Stay focused on the key point is never easy. It has everything, from torment, desperation, and distraction. An educated layman and an expert are of two completely different levels. Improving your skills is never easy. When encountering difficulties or failures, people tend to be disheartened and astray from their goals. 

4. Economic expert Tyler Cowen said in his book Average is Over that the era of "average" is coming to an end. Within years, robots will be replacing humans in all simple and repetitive work. So in order to have a job, you must become an expert in something to the point that no robot can replace you.

5. At school, our teachers want us to be a well-rounded student, and if our marks are not as balanced, we are told to "try harder". However, the school of life wants you to become a master of one. 

6. At work, you often meet these 2 types of manager: 'easy' or 'difficult'. The easy one tends to say 'you are doing a decent job', while the difficult one is less likely to show that they are pleased with your product and they always ask for more. 

Sadly, we tend to be lured by compliments and forget that you are still far from perfect. If you stay pleased with yourself, you will not have any chances to become an expert. For that reason, when you are still in your 20s-30s, focus on one area and become the expert. That is something you will definitely not regret.