Not everyone gives a shit. Okay?
That super awesome video you found that you think every just has to see because it's so amazing?
No, they don't have to see it. Maybe not everyone thinks it's as great as you think.
Or, to make sure everyone notices, maybe you should throw the stuff you find everywhere for people to see. Plastering it all over chat rooms, sending them to everyone via text/group Skype, just to show all the AWESOME stuff you find.
No, you don't have to do that. We don't necessarily think it's the greatest thing ever. It doesn't hurt to share some cool stuff, but please don't share every single thing you find and/or act like it's a fuckin' gold mine of amazingness. It gets annoying fast.
Or maybe you need to brag about that awesome thing you did, or what your friend(s) did for you. Make sure everyone knows about all the awesome shit you're doing.
No, they don't. We don't have to know, nor do we usually care about all the "amazing" stuff that happens around you. Simply telling us about the stuff is fine, but do not fucking BRAG or GLOAT about it like it's the best god damn thing ever since sliced bread.
Or maybe you should brag about your new friends to your old friends. To let them know how these new people do this and that, and how you think that's awesome.
Honestly, just stop right there. Now only are you a piss poor friend for ignoring your old friends, but you're rubbing salt in the wound by bragging about your new friends, showing them off to your old ones, or lurking in front of your old friends to hang with your new ones. I don't care about your new friends, so stop showing them off in front of me.
Now, onto some role playing stuff.
That one character who seems to have issues? Who looks/acts like something is bothering him/her constantly? Maybe it's anger issues, maybe it's something on their mind?
Do not fucking bother them over and over and over and over and over and over and over and over and over again just because you think it's fucking funny. And if you're gonna use some bullshit excuse like "well maybe they should get over it or stop acting like that," then you can fuck off. For one, maybe the character is actually IN CHARACTER and it's not that easy for them to change their personality like that. For another, maybe that character will fucking kill you if you keep treating them like a play toy. Would YOU want to annoy a psychopath with a known history of violence? Tempting your characters' fate just for a laugh is rather fucking stupid, and god modding yourself out of the consequences is plain immature. You can't just attack someone and just "run/teleport away" every time they try to retaliate. Man the fuck up to your dumbass antics. If you're going to annoy someone, you better expect them to retaliate in some way.
Here's a good one. You're really into a fandom/series, likely where your current character is from. So you start putting focus on characters from the same series you're into. But what about the characters from the other series?
Don't fucking ignore them. Everyone who role plays does it because they enjoy it, and the character they're using is really close to them in some manner. If you find like-minded people who're into the same franchise, wonderful. However, don't turn yourself so narrow minded that you think people from other series aren't worth your time or are beneath you. Because, you know what? Maybe some of those people aren't as lucky as you to have an active community. Not to use myself as an example, but since I'm a good one, might as well. BlazBlue is a series with maaaaaaany characters. However, as of right now, the Ask BlazBlue community has fucking died and turned into something I can't even recognize. Me and a few others aside, hardly anyone is active in this family I love so much. The accounts that exist are either inactive, RPed badly, both, or, in a few people's cases, very good but few in number. The good ones are few and far in between. In a series with a potential cast of 20+ people, you're lucky to see 5 people around. So, in a forgotten/beaten family like that, the ones left over look for other people/series to RP with. But it's hard when you ignore them or think very lowly of them. You can keep bragging about how active your fandom is, but keep in mind that for people like me with a small fandom, you're pissing us off. And it's not even limited to fandoms! Don't brag about how your group of roleplayers is so great when other people are lucky to find a decent RPer every now and then!
... This is what happens when you rant aimlessly about random shit on a tired brain.