I definitely wanted to slap the shit out of Andy in Season 1 for taking advantage of Ann's kindness by pretending his injury was lasting far longer than it actually was. Yes, he immediately got more likable in Season 2 and beyond, but Season 1 Andy was a fucking tool.
At least in the Thanos situation, we're talking about a guy who just discovered his girlfriend was murdered by the man right in front of him, and this was actually brilliantly set up in Guardians 2 when Peter discovers Ego is responsible for Peter's mother's tumor that cost her her life and thus Peter immediately opens fire on Ego. In Guardians 2, it's a triumphant moment for Peter, but in Infinity War, we see how that sort of knee jerk reaction to realizing a murderer of one of your loved ones is right in front of you could actually make the situation far worse. It was actually quite clever writing, and good use of established characterization.