Several categories evoke that reaction:

Moments of fantastic beauty/happiness: music, opera etc. imagery (nature), or even a short/long story. For example, yesterday a friend had me read a short lecture she gave to her fellow medical professionals. It was an uplifting moral lesson with a touching ending. - - I, like her fellow workers, had tears in my eyes.

Recalling (usually while retelling) traumatic losses of others who needlessly suffered or died. Some funerals where a young person has lost a caregiver.

Reading fiction: Dumbledore's funeral was crushing

Dealing with my own personal loss of those I care/d for. I can not recall such a reaction as an adult but I probably had tears in my eyes at some point.

...i could always "let go"at a burial site of
parents/sibling; after long periods of acute
stress it also arises; triggered by sentiment....