Complainer -- someone who doesn't want to take "no" for an answer, and tries to manipulate with guilt or having other feel sorry for them to get their way.
Yeller -- someone who absolutely refuses to take "no" for an answer, and woe be it to those who attempt to say it to them.
Why is it that a complainer will rarely complain to another complainer? First, complainers think that if they complain to another complainer that that other person will just complain or make an excuse about why they can't help. Second, complainers perceive themselves as weak and perceive other complainers as weak and therefore don't see that another complainer has anything to give them.
Instead complainers will usually complain to yellers. Why? Because complainers perceive yellers to be strong, powerful and having something to give them. They also believe that that a strong person will either intervene on the complainer's behalf, take care of something for them or let the complainer off the hook. The real problem that complainers don't realize is that yellers are often not strong, they're just angry.
What's the solution for you in dealing with a complainer or yeller? First, don't expect them not to react in a negative way (by complaining or yelling) if you want something from them that they don't want to do or give. Second, after they complain or yell at you for something, calmly pause for at least 10 seconds. That will drive them crazy, but rather than being frightened by them, see that as a temper tantrum at not being able to manipulate you.
If they do escalate and complain or yell louder about why you're saying nothing, respond by saying, "I'm just trying to figure out what you're so frustrated about and what we and most likely you can do to make the situation better."
There is a good chance they won't like your saying "we" or "you" to them, when what they really wanted was for you to take care of the situation by yourself. If that is the case, they may become even more upset. But if you notice carefully, you will begin to see that they are more frustrated than angry, because they know you have caught them, refused to be manipulated and they don't have a backup plan.
If they do throw the situation back at you to fix or say they can't do anything to make their problem better, calmly respond, "Sorry to hear that, because I certainly don't have any room on my plate to take care of this for you, so we'll either have to figure out a way for you to handle it or you will have to figure that out by yourself and then handle it on your own."
If they continue to dig their heels in or even attack you, calmly respond, "Look, I'm sorry you feel that way, but it doesn't change anything. Either we figure out what you need to do to make it better, or you will need to figure it out and handle it on your own."
If they still refuse to cooperate with that (i.e., their last ditch effort to manipulate you) and even threaten to do something harmful to themselves, tell them, "Well I hope you won't do that." If they threaten to do something to someone or something else, say, "If that's the case I'll have to deal with that appropriately." If they threaten to do nothing, say, "If you do nothing when it is your responsibility and it blows up or turns negative, you'll have to deal with it or pay the consequences. I'm sorry if you don't like that, but it's what all of us have to do when we are responsible for something."
By the way, you might wonder why yellers don't yell at other yellers. It occasionally does happen, as shown in the iconic movie The War of the Roses, but as that film demonstrates, left unchecked yelling versus yelling can beget violence.