Gaming OCD? We got it!

[Psychotic]

Do you also talk to them multiple times, and after events happen in the town, in case their answer changes?

...yes. Also every object in houses and stuff must be examined in case it has a description. In my own games I've made (RPG maker is awesome) I added descriptions to random objects and changed NPC dialogue after events just for OCD people like me.

On Resident Evil, I will use the crappy pistol all the time through the game, hoarding all other ammo, because goddamn it, I WILL NEED IT LATER. Then I find myself at the end of the game with enough weapons to start a small war.

This too.

[Tama2]

In FF games, whenever I find a store I need to get the same amount of all item types as far as my money lets me. For example if I have 16 Eye Drops, 18 Echo Screens and 5 Softs, I'll buy until I have 20 of each status recovery item because 20 is the nearest higher number that is even enough. Sometimes if I've received extra items (e.g. if in the above example I have 22 Antidotes I'll sell 2). If I get really rich I'll do the same with equipment although the number is usually 3 or 5 or something like that.

I do this too, in multiples of five.

I do this too, in multiples of nine, to reflect my fanboyism.

Multiples of 10 for items are preferable, though 5s are also acceptable and 99 is okay too. Equipment requires multiples of exactly one.

I do 10 for almost everything except for reviving items and high healing items. Which I do in 5.

[The Unknown Guru]

Every NPC must be talked to. They all say nothing of value. But I don't care. I must talk to you. In the case of Oblivion, I also had to make them all love me. Argh.

Same here. I also HAVE to check every flower pot, jar, or crate in every town in case there might be 7 gold or some crap like that in there. Golden Sun is tough for me to play until I get Reveal.

A game that deserves special mention is Skies of Arcadia. It's so hard to not walk around in dungeons until every bit of the map is filled in. Also, I MUST see every description in the game, and every time my ship gets upgraded, I have to fly around for hours looking for discoveries.

[Levian]

On Resident Evil, I will use the crappy pistol all the time through the game, hoarding all other ammo, because goddamn it, I WILL NEED IT LATER. Then I find myself at the end of the game with enough weapons to start a small war.

Yeah and

I feel bad mixing two green herbs together, or any two herbs that aren't green or red really. I don't like using F-aid sprays until I'm all out of herbs. In the item chest I need to have similar items next to eachother. Herbs, guns, ammo, old keys that I for some reason decided not to discard. There can't be spaces between items. Ink ribbons needs to be combined. I can't use machine guns or any other stronger gun unless all of my shotgun shells are gone, and even then I'd probably turn to my handgun before I used anything else.

[Shoeberto]

On Resident Evil, I will use the crappy pistol all the time through the game, hoarding all other ammo, because goddamn it, I WILL NEED IT LATER. Then I find myself at the end of the game with enough weapons to start a small war.

Yeah and

I feel bad mixing two green herbs together, or any two herbs that aren't green or red really. I don't like using F-aid sprays until I'm all out of herbs. In the item chest I need to have similar items next to eachother. Herbs, guns, ammo, old keys that I for some reason decided not to discard. There can't be spaces between items. Ink ribbons needs to be combined. I can't use machine guns or any other stronger gun unless all of my shotgun shells are gone, and even then I'd probably turn to my handgun before I used anything else.

Pretty much the same, through and through. Though occasionally I just get fed up with having so many green herbs without any reds to mix with so I might make a 3 green mixture but it always seems like such a waste. And yeah... I try to use the pistol on zombies and dogs, shotgun for anything stronger. But no magnum or anything heavy until the final boss... then I always have like crazy amounts of magnum/flamethrower/grenade launcher/etc. ammo.

[Værn]

If there is a bestiary, then it must be full.

Gotta catch 'em all...?

In games where you are able to manually adjust your stats upon leveling up, I try to keep them all at multiples of 5.

[The Man]

I'm really obsessive about hoarding ammo in FPS games. If possible I'd go through the whole game with fists only even if it made me take five times as long to complete the games. I also have to complete the automap in games that have them and I have to talk to every NPC multiple times and check every flower pot for bonus stuff, regardless of how much I need it. I also feel compelled to pick up all bonuses that enemies drop regardless of whether I actually need them. Even in the original Zelda when you're limited to 255 rupees, I still freak out if I fail to pick up a coin.

[Wolf Kanno]

The item inventory stuff people have mentioned as well as talking and examining everything. I must complete auto-maps, I must get every treasure in the dungeons. If I know a creature has a weapon/equipment rare drop, I will spend hours farming it until I get what I need. In tactical games, I will restart if I lose a character or item, or even if its not permanent, if the battle was easy and I lost them due to carelessness, I will restart it so he gets the XP. If the game has job classes, I must master all of them, if it has ultimate weapons, I will obtain them even if I don't use them.

I must have one of every item that is gettable in the game, from obscure item drops to useless things that take up your inventory space but doesn't do anything. Whatever customization system there is, I will generally play them until I deem them broken. Unless of course its more of a time sink than I am willing to give (Disgaea series). I must collect every coin/ring/ammo/small child whatever is hanging magically in mid-air surrounded by death from all sides, I will go for it. I never use E tanks until the final boss, I never use magic until a boss battle or until I absolutely need to. I never use items like elixirs except when dealing with Magic Pots.

[Zeldy]

When playing an RPG, I buy as many HP items that you're allowed to carry. Same goes for phoenix downs, ethers, my brother called me for it. I don't call it OCD though, I just wanted to be well prepared!

[Jessweeee♪]

I think Persona 3 is the only game where I haven't saved every good item I have ever until the last boss where I still don't use it. I think I'm near the end of the game now and I use all my good items in pretty much every boss battle xD

[Wolf Kanno]

I think Persona 3 is the only game where I haven't saved every good item I have ever until the last boss where I still don't use it. I think I'm near the end of the game now and I use all my good items in pretty much every boss battle xD

Persona 3 makes you rethink alot of your RPG OCD. I know I didn't really reserve items in that game.

[Goldenboko]

Reloading OCD. I have it. Missing one bullet in that Assault Rifle? IT MUST BE REPLACED! I don't care if my team needs my support, it might come down to that one LAST BULLET!

[Rase]

As several have said, I have the "multiples of 5" condition in RPG's (items) and RTS's (units).

[Lawr]

Playing Legend of Dragoon and viciously collecting Star Dust now gave me the OCD of checking every vase, bookshelf, flowerpot, and corner.

I also like to buy/sell healing items up to multiples of 10 and I always keep my old equipment and never sell it.

Edit
Oh yeah, I also have a reloading OCD in shooters. Even if I have the chance of being killed while I reload, I always have to have a full clip. Always.

[Jiro]

I have the reload OCD too. I reload as soon as I kill someone, even if there's someone else already there, a really bad habit.