Ta is my irk. I always say "thankyou" to DS hoping that he will repeat that one day (he can't say anything at the moment). But my parents say "ta". It might be easier to say ta, but he has to learn thank you some day... so I don't want him to learn ta now, and thankyou later on.

I never thought about many of the others you have all mentioned. I'm a culprit with some of them.... ni ni. But then, I think I would say that to my husband