Meet Bob. Bob is a solid healer, reliable raider and all around good guy. Meet event X that affects Bob's performance, attendance, or attitude. What does a RL/GM/Friend do about it?
What do you do? How do you keep the guildie from disrupting normal guild operations while trying to salvage what was once a great asset?
Get the Scoop:
Before jumping to any conclusion get the story straight from the horse's mouth. Don't go by what Officer Tom said because Officer Tom is a bastard and will lead you astray. You want your information straight from the source. If it's something extremely personal that they don't want to talk about that's okay. At least now you know it's a personal issue outside of your sphere of influence. If the guildie has a problem with you personally then try to address it and if you cannot call in a trusted officer to mediate.
When they explain their situation you need to listen. When I say listen I don't mean the kind of listening you do when your wife starts giving you a list of chores or starts talking about feelings (whatever those are). Make sure you completely understand the situation and ask them to repeat things as necessary so you can fully grasp what's going on. As much as you might want to don't give any counter argument or really do anything but ask them to clarify statements until they have finished and you understand what they were saying. You want a full picture from their perspective.
Lay down your side of the argument and be completely honest with the person. Honest doesn't have to be harsh though. "You've been a total ass in G-Chat." is a very ineffective way to say "You haven't been yourself lately and you've been taking it out on people in G-Chat." Your goal here is to point out how they are impacting the guild not to point a finger and call them a d-bag. Have you ever heard the phrase "You catch more flies with honey than with vinegar."? This phrase applies here. If you put them on the defensive your conversation is likely to end badly.
Remember Past Triumphs:
Give them credit where credit is due. If it's a solid raider who's been with you since Vanilla and they're just having a rough spot then that's something to take into consideration. Even if you're not in a guild that's "friendly" consider the investment the guild has made in this person. From a cost/benefit point of view it makes more sense to try and salvage the relationship rather than write it off. Whenever an issue arises try to think what would happen if you took a raw recruit and put them in that player's position.
Forgive - Don't Forget:
Forgiveness may be divine but forgetfulness is stupid. If this is a consistent behavior then it's something that shouldn't be tolerated. People who constantly jump across the line and cause guild disruptions are cancers that need to be excised.
One Last Chance:
In my guild when someone is on the brink we have what is called a "Come to Jesus Meeting". This is where we let them know that their behavior is jeopardizing their status as a member and they have one last chance to get their act together. You lay down exactly what needs to change. It's a good idea to ask what you can do to help but only if you genuinely will help the person. Ask them what they need to be able to make these changes if they are even willing to in the first place.
Cut Your Losses:
There's a time when it's just better to part ways with a player. Try to make it as amicable as possible. Unfortunately we all know that this isn't always the way it goes. Minimize guild disruptions and be honest with the rest of the guild as to why the person was removed. This is particularly tough to do with the formerly good player but you once again have to weigh the cost vs. the benefit. Remember guilds are made up of a group of people and one person should not compromise the experience of everyone else.
It's tough dealing with a rogue guildie, even more so when it's a good guildie. Just remember to keep everything in perspective (this is a game after all) and approach the situation with a clear head. With calm clear thinking almost any problem can be solved with minimal drama.
It's a problem many of us have seen. In a more hardcore guild it's not really all that much of a problem. The player who doesn't perform doesn't raid and the person who acts like a hygiene product usually gets kicked. In a non-raiding casual guild it can cause varying levels of damage depending on how big a part of the guild the person was. I wish I could throw some RP guild experience in here but sadly I can't. It would seem though that an attitude problem would be extremely detrimental to roleplaying though.