I got emotional with pretty much every one, but the ones that really hit me hardest were Stanley, Alice and Mickey/Bruce. Each one because it was very easy to see people from my own life in each of them.

Stanley reminded me of a young boy whose family I worked with after he was diagnosed with a terminal illness. Having seen the way that their family dealt with it from the other side, it broke my heart to relive.

Alice reminded me immensely of my Oma (something she seems to have done for other people in regards to their own grandmothers) especially towards the end when she was suffering severe dementia and commonly confused me for her baby brother (who had died in WW2) and had severe osteoarthritis that lead to many walks like what Stella does for Alice. Reliving that tore my heart up all over again

As for Mickey/Bruce... in some ways they reminded me a ton of my twin cousins (on the other side of the family) who were totally inseparable growing up. Not from an 'organized crime, part of the mob' angle, but from the fact that the older of the two (by like 20 minutes or something) was the quiet 'big guy'-type who had quite the temper and the younger was more of the frenetic charismatic one. One of them was in a pretty nasty car accident a few years ago (in this case it was the younger 'hummingbird' brother) and ended up in a persistent vegetative state. I've seen how my cousin has declined over the years and he has this oppressive air of utter sadness around him. I've been trying to talk him to going to therapy to have the tools to deal with the potential that his brother will pass on without regaining consciousness, but I deeply fear for him.

So yeah...

tl;dr: Stanley, Alice, and Mickey/Bruce. Because of life experience reasons.