Anyone with the least sensitivity to human interaction can tell that something's amiss if I'm aware that I'm bending the truth even slightly. You don't need a polygraph with me; if I know that I'm lying, or even being evasive, it shows.
This can make keeping other people's confidences pretty difficult for me. No, I won't spill the beans - when I give my word that my lips are sealed, sealed they are and sealed they remain - but I'm distinctly poor at being evasive or coming up with neat conversation-diverters.
Look, there's a plane!
See what I mean?
Quite often I can get round this inability by being straightforward and saying "I can't tell you about that", which is, thank goodness, the truth - I've promised that I won't. But in certain circumstances that would be tantamount to a Big Red Flag, wouldn't it? You come out with that, and it's pretty evident that you've got something to hide.
It's not that I want to improve my lying skills, but I'd really like to know how people handle that kind of thing. I've been put on the spot like that once today, and I'm still twitching about it. I think I managed not to blow it, but...