He is working with chemicals, so you stay back for a bit, watching.

"I used to teach chemistry, y'know. But this job is more fun."

He says this in a nice tone. He is happy to have you stop by.

"So, what did you need?"

He pauses what he was doing, and gives you his full attention. His gaze met your eyes, and you could tell that he was completely focused on just you now.