The Gottman Institute did a lot of research on the effect of accepting bids (putting the glass in the sink), ignoring bids (leaving the glass out), and rejecting bids (throwing the glass against the wall and arguing), and they determined that accepting a bid added one feeling dollar (my term) to the bank account of your marriage (my metaphor), while rejecting a bid took five out, and ignoring a bid took like ten or fifteen out.
TLDR: Ignoring someone, or causing them to feel ignored, is more painful than intentionally being mean to them, because even that is a form of acknowledgement or attention. Also, you need to keep putting feeling dollars in the bank because you never know when you're going to have a huge fight, have your partner check the balance, and decide there's no reason to keep going.