But yes, I've used the incompetence tactic my whole life, or at least just never try very hard at something I don't want to end up doing.
And yeah, I'll drop everything to do something that's going on right NOW. That's what causes me to be so unreliable, though. If you want me to do something, you pretty much have to tell me right when it's happening... I'm great at just running out the door last minute. Unless I'm already doing something else I want to do more, of course... haha.
I'm usually the one initiating activities anyway, though.
If a relationship isn't voluntary on both ends it just isn't worth it.