To respond to your earlier question, I have a couple friends I flirt with, and while some joke around about it, others ignore it, and some give me the cloudcuckoolander treatment for it, it has never had a negative effect on my relationships with them. The only friends I flirt with—often with "accidental" innuendo, my favourite—are the ones I [i]know[/i] so well that we can really do anything with each other.

There's really two levels to this, that I guess I might as well mention. First of all, important things to note: I am a male interested in females, and it is well-known by basically everyone around me in real-life that I have no intention of forming a romantic—and even less, a sexual—relationship with anyone.

Firstly, the most frequent flirting is some I do with one of my best friends. He is male, I am male, and I like to let slip some sexual/romantic innuendo from time to time, especially with observers around, to just mock myself. It goes contrary to what I am accepted as being, and that makes it fun. To a lesser extent, I also do this with my [i]brother[/i] in the Skype Group, for much the same reasons, with the added fun of him being totally weirded out because incest and all.

Secondly, less frequently, I may do similar flirting when in the company of people I know well, but that aren't in my top-tier friendslist. In those cases, I am always quick to "divert the flirt" so they understand I wasn't serious. By creating a flirty situation, and then quickly explaining the totally platonic reason I would be doing it. And it works because the know that I'm joking, and they also know I'm serious about the platonic stuff.

So all in all, the friendly flirting without end goal works largely due to the targets knowing what's happening, and that nothing will come of it. The few that get weirded out by it usually dismiss it as randomness, and I have no issues with that.