So the FA tells your wife (based on your total post, I'm skeptical that she "hollered" at her; more likely she was trying to talk over the general noise) that her bag looks like it's too big. In return, you and your wife insult her and attack her judgement. Please note that you were the ones who brought up "problem passengers," not her. Shortly thereafter, your wife stops the FA in the middle of the cabin check to essentially say "I want an apology for my own personal offensive behavior, and until I get it, I'm going to ignore you, the person who is responsible for in-flight safety." The fact that you're both over 60 is irrelevant. You may think you're not security threats, but you were aggressively rude to someone who was just trying to do her job. Can't really blame them for deciding not to take the risk that you'd escalate things in the air--you were already escalating on the ground.