I'm someone who this series affected on a deeply personal level. No one character in specific over the course, but overall with the stories it tells. I'm not even in medicine. While the obvious answer is to avoid season 9, aka the season that shall not be named, which started as a spinoff and ended being linked to the original and tarnishing the memory of it. The overall character arcs for just about everyone is solid. The story types and emphasis on comedy or drama shifts, but pay attention to the characters themselves and just soak that in and enjoy it.

There are episodes that, even if I haven't watched recently, I can see even short snippets of, that will leave my bawling. And some that leave my giggling for no apparent reason.

The only other show with that impact on me has been Futurama.