Jack has a dark side, which is that he is both an alcoholic and a drug addict. This creates more conflict in his relationship with Ally, and with his brother/manager Bobby. He pretty much destroys his life, but then goes into rehab.
On a technical level, the movie is fantastic. The chemistry between the two main characters, played to perfection by Bradley Cooper and Lady Gaga, is just wonderful. The singing is top notch. Both characters are portrayed as the nicest people in the world, except for the few times when Jack is taking a nosedive into self-destruction. The supporting cast is also very memorable.
However, this is where I had a problem with the movie. None of this feels realistic. Ally is supposed to be this uber-talented singer-songwriter who lacks confidence and is too meek to appear onstage, despite giving a knockout performance at a nightclub at the beginning of the movie that doesn't seem shy at all. These personal attributes don't go together, because people who are super talented know it and live for the moments when they can best use their talents. On the other hand, Jack is way too nice of a guy to be an alcoholic drug addict. In the real world, this would be pretty ugly.
The movie gives us a tragic ending, but the emotion feels all wrong like the film glosses over the devastating emotional impact that this would have. I am also bothered by the frequent foul language. Normally that would not be much of a problem, but here it is gratuitous as if it is in the wrong movie.
There is so much to like about this film, but taken as a whole its many elements don't mesh together as well as they should. It could have been perfect, but instead it feels flawed.