Immensely harder to build something without a flaw than to find a flaw.
Also, I'll note that the criticisms we level while we review some work in privacy are not reviewed in their turn by anyone else. There should be some humility in your "gotcha" if it has never faced criticism of it's own.
On the other hand, if you're a very good critic, it becomes very hard to create something, as you see flaw after flaw after flaw, multiplying faster than you can fix them. I find it very hard.
I think there's something to that archtype of writers as drinkers. Got to shut off that critic if you want to get anything completed.
When I criticize, I'm a genius. I can go through a book of highly-referenced scientific articles and find errors in each of them. Boy, I feel smart. How are these famous people so dumb?
But when I write, I suddenly become stupid. I sometimes spend half a day writing something and then realize at the end, or worse, after posting, that what it says simplifies to something trivial, or that I've made several unsupported assumptions, or claimed things I didn't really know were true. Or I post something, then have to go back every ten minutes to fix some point that I realize is not quite right, sometimes to the point where the whole thing falls apart.
If someone writes an article or expresses an idea that you find mistakes in, that doesn't make you smarter than that person. If you create an equally-ambitious article or idea that no one else finds mistakes in, then you can start congratulating yourself.