Be appreciative
I think this phrase 'thank you' has lost its appropriateness. People are not feeling appreciative or warm to the feel of it. It just that mundane thing to hear someone saying "thank you" to you sometimes.
Let me explain more.
Words are powerful stuff and when our words affirm what is good, what is right in our world, they solidify that goodness into reality. Do not underestimate the power of your spoken word. Worlds and universes are created from this magical process. Notice that in this realm, in our reality, we are the only known beings to transform thought into a spoken language.
So have more appreciation next time when someone does you a good deed. Reply with a big smiling thank you!