One of the reasons that caused the stress is fundamentally works because some people may receive the job do not match the capabilities of the knowledge itself or sometimes caused by requiring everything works perfectly. When done, it was the stress.
One reason is that the work load stress, some people may get the job do not match the capabilities of its own. Sometimes, due to the need to run all the way to perfection. When doing so stressful.
One of the reasons that caused the stress is the burden of work, because some people might get work does not match the competence of its own. Or sometimes due to work everything to be perfect. When do the stress.