Is the following sentence correct?
If there is anything unnatural, could you correct it for me?

"When customers say 'thank you' to me, my tiredness goes away."

Thank you!

Question

Is the following sentence correct? 
If there is anything unnatural, could you correct it for me?

"When customers say 'thank you' to me, my tiredness goes away."

Thank you!

Answer

Some other natural ideas:

Customers thanking me gives me a burst of energy.

The appreciation of customers motivates me.

Kind words from customers are motivating.

Answer

The grammar is is fine, but it doesn't really sound like something a native would say. There are lots of ways to express the thought. You might say:

When customers thank me, it keeps me going.

When customers thank me, I forget that I'm tired.

When customers thank me, it makes my day.

Answer

It's better to focus on the positive. "Tiredness" is a negative.  "Energy" is a positive.  For this reason it sounds better to say "my energy returns".

ご自宅で快適に語学を学べるチャンスをお見逃しなく。経験豊富な語学講師陣の中からお選びいただき、今すぐ最初のレッスンにお申し込みください！