Mary Watson and Watson in “Unfinished Business”

I know you think that I don't like your new career.

Watson

To put it mildly.

You're right, I don't like it, but not for the reasons that you think. I'm not happy that you're a sober companion, because it never seems to make you happy.

Watson

How do you know what makes me happy?

I know because you're my daughter. After you left medicine, after what happened with Liam, I've always thought that this job was something that you picked out of, I don't know, out of a sense of duty. When you came to dinner the other night, when the two of you talked about Sherlock's work, I saw something in you. It was a spark. A sense of excitement. I haven't seen that in you in a long time. You like what he does.

Watson

Yes, okay. I enjoy it, but I'm not a detective, Mom, and I'm almost done working with Sherlock and then it's on to another client.

Will the next client make you happy? People find their paths in the strangest of ways.