This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / B.J. and the Bear
The episode "Bear Bondage," which aired midway through the 1979-1980 season, had a tearjerker moment in it, when – after he takes Bear to a veterinarian clinic to cure indigestion – BJ is told that his beloved chimp has died. BJ leaves the clinic in near tears in the episode's tearjerking moment, but later realizes that Bear may still be alive after he and the babelicious desk clerk (a college student who is studying to be a vet herself) uncover the vet's scheme of selling animals to a laboratory for "research," after telling their owners that their pets didn't make it. (This happens after a distraught BJ has a chance encounter with a little girl, who is reunited with a runaway dog that had also "died" at the same clinic.)