The one on the right really needs her feet trimmed. [Source]
Toe the line vs. tow the line.
Spinster aunts tend to use the former to connote a gesture of defiance, as in scraping a line in the sand with the toe of your Birkenstock and declaring to your opponent “I pity the fool who crosses this line I have just toed!”
The latter, on the other hand, somewhat pejoratively indicates the collaboration of a lackey, minion, middle-manager, or other low-ranking person with a larger entity, e.g. the phrase “tow the company line.” It is believed to be a metaphor of marine origin, likening the tow-er to a horse towing a barge up the Thames, or, even more tragically, a tugboat pulling a Carnival Cruiser of partying middle-managers into Cabo.