What's up with you? Don't you ever say thanks? Doesn't it seem natural to thank people for their efforts and kindness?
You're probably not used to showing your gratitude, or else you struggle to put it into words, either out of modesty or from fear of being indebted to people. Shame!
Not only are you missing out on a lot of extras; you're also missing out on the pleasure you get when you make people happy by thanking them! You need to take some gratitude lessons and learn to say thanks when you need to as well as in less obvious situations.