But...what IS a dickhead?

 A long time ago, I wrote this post. The advice it contained was, in summary, as follows:

As a rule I tend not to read much 'GMing advice' on blogs, because I think it all boils down to something rather simple: play with cool people who are your friends, not dickheads, and don't be a dickhead yourself. Mostly it all works out fine from that initial foundation.

For some reason this came back to me the other day while driving, and I started making a list in my head of the behaviours that would constitute being a dickhead. The irreducible core of dickheadedness, if you will. I offer some suggestions; you will I am sure have your own:

• Dickheads bring sexual content into a gaming session. This is one of the fairly large number of things that traditional conservatives and woke types can merrily agree on: don't bring up the issue of sex unless you are really sure it's appropriate. And never bring up the issue of rape at all, because: why are you doing that other than to either be deliberately edgy, or be a creep?
• Dickheads hog the limelight. If you feel like you are talking too much, you probably are. If you don't, you still probably are.
• Dickheads don't come prepared. This is more of a DM thing - there is nothing worse than feeling as though you've phoned in a session - but it applies to players too (at least don't forget your dice). 
• Dickheads treat everything like a joke. There's nothing wrong with humour in games. Indeed, "Dickheads take everything completely seriously" is the mirror image of this characteristic. But there is a line. And it is easily crossed. An RPG session should have a rich tonal palette. 
• Dickheads engage in sociopathic behaviour in play. There is nothing wrong with being a rogue. There is something wrong with making the game entirely about how your character robs and/or kills everybody he meets. 
• Dickheads come with a predetermined idea as to what their character is like, what the campaign will be about, and what events will happen in it, and then purposively work to try to achieve that vision at all costs and sulk when it doesn't pan out. (A friend of mine told a story about a person who turned up for a game insisting she be allowed to play a were-badger, and wouldn't accept that it a) didn't fit, and b) wasn't in the rules. This is dickhead behaviour.) 
• Dickheads don't adapt to the tone or context of the game. If everybody else wants a 'narrative' style game and you insist on treating everything like a sandbox, you are engaging in dickhead conduct, and vice versa. 
• Dickheads get way more drunk or stoned than everybody else at the table.

There are also pseudo-dickhead behaviours that can go either way. Being pedantic about your field of expertise can be annoying, but it can also be helpful. A WWII-era game I once ran had a serious gun nut as one of its players. He could have been a dickhead by correcting every tiny error I made as the DM, but in fact he was very helpful in improving the verisimilitude of the campaign. Similarly, being a 'rules lawyer' has the potential for advanced level dickheadishness, but sometimes it can be handy for the DM to have somebody to consult about the rules. 

You are free to add your own suggestions in the comments.