A lot of past experiences of mine have shown that there is little, if not almost impossible, "organic integration" into already happening interactions.
If a PC can't, then maybe don't?
Merchant is selling something to a customer. I have a PC who is rude and intrusive, without social grace.
I can ignore the interaction. I can IC come up and listen to the exchange for a second and then say, "He's bloody cheating you, mate. Why I saw a dwarf selling that for half as much."
Or I can say, "I'm a mighty priestess of the Demogorgon. Convert now or burn!"
The player can say the last is IC, but it's trying to dominate. The second at least attempts to play along with what the first two PCs were doing.
If you listen first you can see whether there's a hook for your character or not. If you're not at all interested in what the first two are doing, do you really have the right to steamroll over it and make them pay attention to you instead?
This is minor anyway. The OOC is worse because the people you're enjoying RP with don't realize what you're dealing with while trying to RP with them.
I've pretty much said all I want to say on this. Since Miuo is confused, please excuse all the personal venting in my previous post. Here's the short version:
If LFRP is off, maybe the player isn't LFRP???
Can you integrate your RP with others, rather than dominate their attention or feel left out?
Are you using OOC rather than putting the effort into RP that IC requires?