What does this sentence mean? " It will serve you well when you take me to the dentist tomorrow."
Do you guys watch "The Big Bang Theory"?
Season5 Episode15.
Sheldon says " It will serve you well when you take me to the dentist tomorrow." What does this sentence mean? Does that mean, "I'll treat you well tomorrow when you take me to the dentist."? Or, "I'll allow you to take me to the dentist, because you've been nice to me."
Thank you so much~

Question

What does this sentence mean? " It will serve you well when you take me to the dentist tomorrow."
Do you guys watch "The Big Bang Theory"?
Season5 Episode15.
Sheldon says " It will serve you well when you take me to the dentist tomorrow." What does this sentence mean? Does that mean, "I'll treat you well tomorrow when you take me to the dentist."? Or, "I'll allow you to take me to the dentist, because you've been nice to me." 
Thank you so much~

Answer

Damon-MJE

You didn't give us enough of the dialog to determine what "it" refers to. I had to look up the episode and find the missing reference.

Here it is.

-  I saved you a dumpling.

- Oh, your concern
 for me is touching.

It will serve you well, when you take me to
 the dentist tomorrow.

- I'm sorry, Sheldon, I'm busy.

---------------------------
It = your concern for me.

Your concern for me will serve you well when you take me to the dentist tomorrow.

will serve you well  = will help you or benefit you

Answer

Sheldon says taking him to the dentist will bring benefits. The nature of those benefits remains unspoken.

Answer

We use this expression to mean that something is useful, or will bring benefits as Randy said.
e.g. " One time I got lost in Paris. But it was OK. All those years of school French lessons served me well." = the school French lessons were useful in this situation.
Sheldon is saying that something (it) will be useful when the other person takes him to the dentist tomorrow.