Stress
Yes, there is plenty of that. Not only are arborists concerned about the sort of damage that they can do to whatever happens to be below the trees that they work on, but they're even more concerned about the safety of their co-workers (and themselves).
As we mentioned before, trees can do serious damage to houses and cars (and goats), which is one of the many reasons the insurance premiums are so expensive. The other main reason for expensive premiums is that trees can also damage or kill the people who work with them. That's probably the most stressful part of the work. Arborists rely on each other for safety; and their co-workers are very, very, very important to them.
The work that arborists do is intended to make trees safer. However, there are certain trees that cannot be repaired completely. The risk of falling limbs or even falling trees, and any associated liability, is sometimes a concern long after the work is done.