Guy wants to change girlfriend and then regrets it
 

Okay, so this movie was about a guy that had a girlfriend I think or wanted to have one and then when he got a girlfriend, she turned out to be nothing like him and they'd always disagree. And then one day he gets the opportunity to completely change her and he does. In the end she gets very upset, because she gets so attached that she can't live without him or something like that. I cannot quite remember the plot and the movie name, but it was something along these lines.

Try this: Eternal Sunshine of the Spotless Mind (2004).

https://m.imdb.com/title/tt0338013/

Upvotes pour in, but I’m not at all sure that’s the intended film. The other end of the spectrum would be The Family Man (2000). But that doesn’t fit so well.

https://m.imdb.com/title/tt0218967/

Do you remember anything about the nature of how he changes her?

For example, is this a fantasy, made-a-wish kind of film?
Or more like a science fiction, reprogramming a person kind of film?

And are you sure that this is a film? It sounds almost more like an episode of The Twilight Zone or something.

I have the same question as OP. It's something I saw recently and it wasn't too old. It was as OP described, not at all like Sunshine or Family Man. I thought Time Freak (2018) was what I was thinking of, but is there also a movie that's even more like what OP described than that? Time Freak was pretty much sci-fi. But I'm thinking there was one that was more of a make-a-wish, where in the beginning the other guy asks if he's sure he wants to risk messing with it instead of leaving well enough alone, and it seems weird that his answer is yes, and then at the end he reveals to her why she's been so clingy and she's released from the spell.

Re: Guy wants to change girlfriend and then regrets it
 

I looked these movies up. I do not think it's any of those. It was like.. a sad movie, Idk if it was romance. The nature was more like: A guy liked a girl, but she was very different from him. So he made a wish that she was super attracted to him, his wish came true. Later on in the movie (towards the end somewhere-ish), she would cry because she feels like she never wants to leave his side or something, so she wishes to die or something similar to that. I've watched that movie/tv serie like a very long time ago, so I am not 100% sure if the plot is accurate. I remember it being a movie. I apologize if the title is a bit misleading. :(