I felt that 'Thank You' are an inefficient gratitude, and degrades your character.
Some situations where you should avoid saying "thank you" are the following
- when they're not doing you a favor. (i.e. T.A email student and tell them their hw grade are posted and follow by a thank you. totally unnecessary. a guy returning your pen he borrowed, and you say thank you, not neccessary.
- When you're are demaning something. you're mad that the cellphone company charge you some international calls that you never make. Even thou they fixed, they wasted your time, don't 'thank you' them.
- When they are making profit of you. People will come up to you, or call you to offer this and that (opening a new credit card, cable, car insurance), don't say "no thank you", say "NO!"
- When you really want to thank them. Saying thank you 3 times isn't going to help. because 'Thank You" is overly used, people used too often, even when they dont' mean it.
in situation 2, Thank you makes them feel good. they should be apologizeing. you do not thank people who do soemthing wrong. If you thank them for charging you extra, they will do it again next time!
Too often I got calls from telemarking in situation3. I used to say "no thank you" and those annoying sell person continus to annoy you repecting what he said previously, "Sir, I just want to let you know that this if free of charge for 30 day, and you can cancel it any time you like free of charge. With this you can do.... bla bla.. may i play go ahead and open this account for you?" What is the point of being polite to them? Go ahead and say NO and yell at them.
Situation 4 come the time where some one had really helped you, like a doctor saved your son's life, Some stranger give you money for bus when you got robbed, don't just say 'thank you' like you say to all others. Use some bigger vocaburlry and use some full sentence. and say it with feeling.
There are other situation where you should not say TY. next time just think before why you say 'thank you'