My husband biked home from work this evening at the usual time. He panted into the house, especially exhausted and sweaty after the long chug up the hill. As he walked in, he started complaining about how busy he was at work all day, barely having a chance to take a break, and only eating "one spoonful of peanut butter" and "a pack of ramen" - the only food left in his stash at his desk. I'm sure I didn't help matters by immediately asking him for a favor (to crack my back for me) once he put his stuff down. And though he obliged, he was being a little brusque and, as I perceived it, rather short with me. I was going to say to him, "I know you had a tough day at work, but can you please not take it out on me?".
Me: [while Tom was walking the other direction] "I know you had a tough day at work..."
Tom: [stopping] "Huh? What did you say?"
Me: "I know you had a tough day at work..."
Tom: [genuinely] "Wait. You're actually showing sympathy? Wow...that's such a nice change."
And, of course, that totally shut me up. He truly thought that was the end of my sentence. And it really made him feel good. And you know what? Just showing sympathy and then stopping - not adding a "but..." at the end of the sentence: it works so much better! He was so happy that I understood him and cared about him instead of nagging him as usual, that his mood instantly became so much lighter.