Jen, would you have the same question if the conversation had been about a human?

Like this (I tried to select someone who has already passed)

Her: I don't know where people go when they die but I sure hope her parents were there to greet Grandma.

ME: I am positive that they were, just like my great great grandparents and the others were there to greet my great Gran when she died.

Her: BOY, we sure suck at letting go, don't we!

Letting go IS difficult. Whether it is letting go of a child moving out to college, letting go of a parent who passed, letting go of a spouse in a divorce (even when both parties want the divorce, it is full of emotion).

And it is hard letting go of a pet, for those of us (like all PT'ers) who treat their pets like family members. Even if the pet only stayed with us a short time.

Does our belief in Heaven / some sort of After Life, and our reuniting with beloved friends or family members mean that we can't face the reality that they are gone forever??

Age old question, studies in Religion and Philosophy have no definitive answer.
Why should we think one way for people and another for animals?

Not sure if this helps you, or not.