Usually I bring along a laser pointer on job sites with me. The idea behind this is to entertain the pets in the house while I'm waiting on hold to finish the job. I stopped bringing treats since I discovered there's a lot of people who have their pets on special diets. When I use a laser pointer to entertain myself with my customers furry friends it's always been amusing. One service call in particular had me in stitches.
Thankfully my customer was also amused and confused, but she now had a new "toy".