Oh man someone sighed at you, I bet that ruined your poor morning. How about instead of anonymously bitching about stupid shit like this you take matters into your own hands and not go back to that establishment if the employees make you feel uncomfortable, because honestly, no one gives a remote fuck if someone got frustrated with you for pouring liquid in a trash can (which is goddamned stupid by the way).
Pushing a button and watching coffee pour into a cup is about on par with (if not below) the standards of your average fast food employee. Putting big cozy couches and chairs everywhere, playing the latest bullshit "hip coffeehouse" music and calling themselves "baristas" doesn't erase the fact they're basically modern age concession stand workers. Expecting them to do any part of their job correctly is asking far more than the money these broke/unbathed kids make.
This isn't even the first I,A bitching about room for cream. Surely you have SOMETHING in your life that better warrants a complaint. This isn't just first world - it's downright petty.
a 20oz coffee cup should be 24oz sized with a line that the barista stops at so they don't even need to ask if anyone wants room for cream. Anytime coffee is up to the brim those bullshit lids can't help but spray coffee all over me and my clothes.
Why not just give it back to them and have them pour a small amount in the sink they have back behind the counter? Also, here's a little life lesson: if you want something specific you have to ask for it specifically.
http://s1.favim.com/orig/14/attendez-la-creme-basterds-chipmunks-christoph-waltz-cream-Favim.com-183432.jpg