What is the difference between ～てくれる and ～てくれている?


Someone I talked to on the internet said to me:

> あなたみたいに面白いなと思ってくれてるお客さんはいるみたい、たまに…

The person was talking about a sentence I'd said earlier that people would
probably think their restaurant was a nice place to eat at. I tried to think
about why くれている instead of くれる but I didn't understand the reason. I don't
know if there is a difference.

I wonder if the sentence creates a nuance of state, like in 思っている. Would it be
grammatically weird to say 思っていてくれる instead?




思ってくれる and 思ってくれている are different from each other in the same sense 思う and
思っている are different in the following pair of sentences.

> 面白いなと思うお客さんはいる

> 面白いなと思って（い）るお客さんはいる

The latter emphasizes it is a sustained state, as you say. The former, on the
other hand, could be understood as referring to a one-time thing.

You can also say 思っていてくれる instead of 思ってくれている.

> 面白いなと思って（い）てくれるお客さんはいる

This means you are grateful for the sustained state where people continue to
appreciate whatever it is that you offer them. The original sentence with
思ってくれている means you are grateful for their appreciation (hence 思ってくれる), and
that appreciation in turn is a lasting thing. Though the difference is not
that significant in this context, the original sentence sounds slightly more
natural than the alternative to me.




思ってくれる and 思ってくれている are different from each other in the same sense 思う and
思っている are different in the following pair of sentences.

> 面白いなと思うお客さんはいる

> 面白いなと思って（い）るお客さんはいる

The latter emphasizes it is a sustained state, as you say. The former, on the
other hand, could be understood as referring to a one-time thing.

You can also say 思っていてくれる instead of 思ってくれている.

> 面白いなと思って（い）てくれるお客さんはいる

This means you are grateful for the sustained state where people continue to
appreciate whatever it is that you offer them. The original sentence with
思ってくれている means you are grateful for their appreciation (hence 思ってくれる), and
that appreciation in turn is a lasting thing. Though the difference is not
that significant in this context, the original sentence sounds slightly more
natural than the alternative to me.

