You know what, aside from her infatuation with Doc Martin, Mrs. Tishell is a competent character. As a farmacist, she never sold more addictive or harmful medicine without prescription from doctor Ellingham and if her clients wanted to get them, she immediately was sending those people to the doctor so they would come back with proper diagnosis. She also was sharing with Martin information that could help him determine what was wrong with his patient.
I really wish they didn't make her fall into this cliche of having a crush on the main character, especially because it brought the most ugly parts of her into the light and culminated in her kidnapping baby James... but at least they gave her some dignity after that - when she came back after going through therapy, she was shown trying to get over her crush and even started to rebuild her life with her husband.
