As experienced by me, whilst writing the water thread (water was just the jumping off point for the wider ideas, as noticed by Fiona and densely missed by some others) in the heat and flash of a moment of massive anti-capitalist sentiment.
1. If someone criticises something, saying "well, if you have ever used (said thing) you are in no position to criticize it".
This is the laziest thinking possible. It is ALWAYS brought up by some dull-witted idiot in conversations about capitalism ("why don't you go and live in the hills then if you don't like it"). It suggests that unless you completely abstain from any process or activity, you have no footing from which to criticise it. This is idiocy. It is the right of any person to be alert to problems in the times they are living in, and to try to communicate or act upon these problems.
This answer always completely riles me because it's just so incredibly dim-witted. And it comes up time and time and time again, and is never anything more than meaningless and provocative (in equal measure).
2. "Shut up and stop complaining you have it easy kids in Africa would kill for that thing you're moaning about."
OH MY GOD people who say this: SHUUUUT UUUUUUUUUUPPPPPPP. It's the most lazy, irrelevant comment I've ever heard 95% of the time it's uttered. Yes, it is taken as a very, very basic given that we here in the West are lucky compared to many. But that does NOT mean that everything is a basket of fucking roses and we should wander around in a happy daze ignoring any problems that should occur. Life is so infinitely more complicated than this comment allows for that it becomes this oddly comical stock response to anything that requires more than 5 seconds thought, used by people who have absolutely nothing of value to say.
It is very different from a basic appreciation of how lucky we are to have been born into a prosperous country, because it is often used completely out of that context as a way to attempt to quell any dissent or suggestion that things are not OK in this country. As used in that context, it is again absolutely meaningless as a comparision.