I don't have issues if neighbors are loud. As in children playing, music or having people over for a party.
What i can't have, is adults arguing, obnoxious unnecessary noise like shutting close doors with full force or trampling around as if they would be wearing those Dutch wooden shoes.
This is from my perspective, living in an apartment building, thinking about the neighbor living above me.
Edit: once i had a couple living above me. One night they came home late and fucked themselves up the stairs. Slowly.
That was the most uncomfortable experience i had with neighbors.