There are two clichés that always get me.

The first is that 'you can't judge art' which is fundamentally untrue. Art gets judged all the time in a myriad of ways, both internally and externally. If it weren't, how would anyone improve...? What can't be judged is the desire/will to create in the first place. Anyone who makes this claim is bordering on ego, maintaining that what they've done is beyond reproach or criticism.

The other is 'you can't judge me', or rather 'you shall not judge'. This cliche comes from the bibble and is often used to shut down criticism, whether it be from egoists who claim exemption from critique or religionists trying to shut down reasonable inquiry into unethical behavior. The actual passage from which it derives is not actually a prohibition on being judgemental, but rather it is a strongly worded chastisement intended to caution anyone from being judgemental without first getting their own intellectual house in order. It's one hell of a loophole considering many people never consider their thinking as deficient, hence they feel completely justified judging others.