[meerita]

This is a fallacy. If you need to show something to prove or give an opinion or a reason about 2+2=4 then we will have troubles to discuss on anything.

You cannot use argumentum ad hominem to this point. If people has to shown their portfolios or other stuff to prove their skillmanship you're only wasting time and finding on the wrong place to prove your points, since those designs may not apply or be used as a good example to counterattack the main point here.

[droopyEyelids]

We do have troubles discussing things.

Unfortunately, the world is so complicated that we can't make an informed decision based on speech/writing alone, and verification of achievements is one of the easiest and most accurate ways to judge credibility.

[meerita]

We should give opinions based on evidence, proven evidence. The rest are just, personal viewpoints who doesn't care what you prove. I try always to avoid these discussions, but sometimes i feel is a bit unfair to bring up the "show me your X card, sir" to talk about something.

[jakejake]

Well, it is actually an interesting idea. I personally am not a designer yet I feel ok offering my criticism of a design.

[alan_cx]

Since designers are supposed to design for non designers, your criticism is vital to the process.