The book of Job actually has two story lines, not one. The first layer is the well known story of Job, his trials and his righteous relationship before God. The next layer down is the story of Job's three friends, and this tends to get lost because the point is much less obvious. you can be sure though, that the author of Job intended for both stories to be told at the same time, which is typical for any Semetic writing of that time or now. Jesus employs this same story telling technique during the parable of the Prodigal in Luke 15. We make the story about the Prodigal, but Jesus makes it about both sons. Read Luke 15...the NIV starts with, "Now there was a man with two sons...". Same technique here in Job.
So, back to his three friends. At first they do the right thing. Confronted with Job's suffering, they go and they sit with him in the ashes of his home. There are a lot of interesting things happenning here linguistically that we completely miss in english. One of them is the use of a greek word that's used very broadly to mean "to comfort" or "comfort" or "comforting". In this case it's parakalesai (παρακαλεσαι). It comes from the same word that we get parakalete from, which is the word Jesus used when he tells the disciples he's going to send a "helper" after he leaves...the Holy Spirit. It's the same root word that Jesus used in Matthew 5 when he says that those who mourn will be comforted. Culturally the word literally means "to draw alongside" or "to sit beside", and has little to do with our idea of "comforting" now. It has a very intimate, personal connotation...it involves suffering with someone. As Leah Coulter puts it, stepping into the cage rather than dragging them out. This is the biblical idea of comfort, and it can only be worked out in community, person to person.
So, Job's friends start off pretty good, but they just can't resist the temptation to "fix" it. There's a couple of other things going on here too, but we need a little background to understand them. Job could be the oldest book in the Bible...opinions vary on the subject. The theology and cultic understanding and pracitice are very ancient though, that much is clear. At this point their theology would have been that a person was either blessed or cursed by God based on the person's behavior. If you do good things, God blesses you with a good life. If you do bad things, you get sick, your animals die, etc. It's a bit more nuanced than that, but you get the idea. This is Job's friend's starting point theologically. Their actions are motivated by a couple of things:

1. They obviously think that Job's done something but he's hiding it. It's a reasonable assumption on the surface of things. It's been my experience that people do exactly this all the time. Welcome to humanity after the Fall. The problem is this: what we know about people we know from past behavior. We can say, "I trust someone until the person gives me a reason not to", but that's not trust...that's faith. Job's past behavior should indicate to his friends that he's telling the truth. They have plenty of experience with Job, and have no reason not to believe him. So something else is going on, which leads us to...
2. Here's the thought between the lines, the one Job's friends are truly motivated by but don't want to express: If Job is as good as they know he is, and he's suffering for apparently no reason, then what about me? Ahhhh, now there's a motive that justifies the interrogation in the next 33 chapters. Of course, what they're missing is perspective, which God, in a grand theophany, offers beginning in chapter 37.

In this age, as the Kingdom has come, but not in its fullness, we still experience suffering and see a world "groaning" under the weight of it, as Paul puts it. We want to "fix" things, but this is almost never the right thing to do. God fixes things...Jesus shows up, he touches someone, and that person is never the same again. All we are is the warm-up act. What Jesus wants are comforters and helpers...hoi paraκaletoi (οι παρακαλετοι). What we get when we have a whole bunch of people trying to fix each other is generally a whole bunch of messed up people. Sit. Be quite. Listen, don't talk. Resist the urge to fix it.