Is this something that everyone does and i just haven't noticed it, or is my friend (possibly soon to be ex friend) odd.
Frequently she will say something and then later when she says or does something contradictory she denies every having said the first thing and tries to make me doubt my own memory. For example, and these are trivial things but they add up, she's told me she really likes cycling in cold weather and then a couple of months later said she can't come out because she hates cycling in cold weather, she really liked a new colleague then started denying that she'd ever liked her (actually this has happened with a few people), she definitely wasn't going to an event and then when i turned up there she was, or she'll say i always do 'x' except always means only when it suits her.
Of course people change their minds but instead of saying oh yeah I've had a change of heart because of blah blah blah, she will say no you're getting it wrong, I never said that. Occasionally i challenge her but it just becomes her word against mine. She has been a good friend to me in the past, and I've got quite a small circle of friends in my local area anyway, so I'm not sure whether I'm putting up with more than i should or whether I should just let it go and except that we have different perceptions of the world.