If you can sit at the computer all day then yes possibly. Buying and selling, trades, services or jobs, and even mining if you can afford the hardware
But that would be stressful. Just 8 hours of working in front of a computer makes your back and your eyes tear. Working for bitcoin for a little time would be great specially if you are just doing trading.
Obviously someone cannot sit infront of computer 24 hours a day or 360 days a year. It is simply not that simple.
Someone gets tired even if he is working on some project or something and spending all his time on computer for just some days.
Better to just make a time table for it if you really want to do nothing else then this.