What do you think multitask is good or bad?

I feel it's good because you can't bore to do work. You can keep enjoying your work explore new things and learn a lot. Where some of the people believe that multitasking reduces your efficiency and performance because your brain can only focus on one thing at a time. When you try to do two things at once, your brain lacks the capacity to perform both tasks successfully. What's your thoughts on it. Please share...