Well said HD!
Stress and pressure are definately two different things. Some people thrive on pressure. Nobody thrives on stress.
Many people (me included) in ATC are able to cope with pressure and are happiest when under some pressure, its what makes the job great sometimes.
As HD has said, some people will handle the stress of life well but can't handle the pressure of this job.
When people ask an ATCO what they do for a living and they tell them, their first reaction is usually "I bet that's stressful."
On its own the job is not stressful. Include all the other stuff that goes on in people's lives like children, money, health and job security and sress will probably manifest itself in some shape or form. That can be said of any occupation added to the above worries.
Age 34, some grey but not balding...yet!