We need to working smart and working hard. You must have a smart brain before you start work and you need a strong body to work hard. To avoid stress think positive always all the thing you have to face because being positive will help you to work in your job.
Actually i agree that both type of working are really help to gain maximum income.
We will get less if we apply only one of them.
But for me i would prefer to work smart because i can gain much income without doing some hard work.
Relax and enjoy the job and get maximum income.