I have to deal with each angry/wont calm down person differently. The woman you described could have been my mom (although she usually wouldn’t knock something off the counter on purpose). With someone like her, I don’t try to get a word in edgewise, I just zone out while she rants (it’s best over the phone, then I can play spider solitaire), wait till she’s done, and make an empty promise to try to fix whatever she’s pissed about, or if it’s not my fault (hallelujah) then I say something about being sorry she’s having to go through that. Besides zoning out (The trick is to not show it, but it really helps you keep your patience and not flip out at them back), the other thing I do is try to end the encounter as soon as possible, ie. get her the thing, repeat that you’re sorry she had to deal with that, and excuse yourself.