Having worked in film and commercial productions, I have to admit that's one of the most challenging jobs I have experienced.
The level of professionalism, the high standards and requirements that are part of the process are very demanding.
That applies to actors and supporting teams.
As for dogs; this can be amplified a lot.
For a TV commercial where the dog appears for a few seconds, the scenes must be repeated tens of times to get the right angle, the expressions etc.