You know that guy in the office who does nothing but complain? I don't mean once in while, but all the time? Bitch, bitch, bitch. Nothing is good. The world is going to hell. The company is failing. The bosses are all jerks. The clients are idiots. The products suck. Yadda yadda yadda.
That's what we call a chronic complainer. They don't just complain, they reject any and all solutions. It can be wearing - and depressing - to be around these people all day.
Sometimes they don't really want a solution or advice. They just need to vent. If you can stand it once in a while, let them vent and get some entertainment from their complaints. You can figure out whether they are really looking for a solution by using the formula:
(AGREE) "Yeah, that is a problem."
(EMPATHIZE) "You've pointed this out before and it's still an issue".
(INQUIRE) "What do you think is the solution?"
If they really care about the problem, they'll engage in finding a solution. If not, they'll tell you it's hopeless. That's your cue to leave.
On the good side, some highly-critical complainers actually do see problems that others are missing. You'll have to use your own judgment to determine whether they are right or just a pain in the butt.