Hmm...
She asked me if she could date a guy I was very close friends with (She also incorrectly assumed I fancied him).
I said no, because I knew the attraction was not him but a/ taking something from me and b/ she didn't really view him as a 'real man' (rebound relationship from a 'real man' who treated her like crap).
She ignored me (well, why ask), went out with him, treated him like shit, made him feel awful then dumped him (which is why I'd said no)...
He and I are still friends 20+ years later, she and I haven't spoken since that night.
From a similar era, friend and I used to do lots of stuff together, each others houses once a week... then she got a boyfriend. Fine, I had one, not an issue..
However she worked full time and he lived a good hour away, she was busier than I, so I said 'well, you call me when you are free, cos I am almost always free'... after I got sick of being dumped for him...
She didn't call.
I er... posted on an internet forum we both use, advertising for a new sidekick, which I thought was funny.
She didn't. We talk now, but it ain't the same!