It's an excellent ability if you can focus on something, so you can achieve desired results.
On the other hand, it's important to be able to change the focus quickly to something else. Women are usually good at this, men may need more practice.
Focus but at the same time don't focus when required, be open to opportunities and events that happen to your environment.
Have focus but be agile at the same time.
There are some scenarios in life that you shouldn't be stable on your focus, you should be able to be aware of your environment at the same time of doing your job for instance.