A snake in the bosom, that's what she'd been harbouring. She ought to have known that Frodo came to her Saturday afternoon tea parties not to fulfill his familial obligations, but to pursue his rakish ways.
How dare he waltz off with the best cook in the Shire, not only right under her very nose, but through her very own parlour, where everyone could see them - not to mention what they'd been up to, and in a broom cupboard no less. She would never live down the humiliation, and as she informed her son Lotho, the next time she set eyes on her nephew, he'd be sorry. Very sorry indeed.
Only the next time she set eyes on her nephew, he was locked in a torrid embrace with her former cook, right there in the middle of the Bywater Road, bold as you please.
The choice words she'd been storing up for their meeting emerged as incoherent, apoplectic sputterings, and when she saw exactly where Frodo's hands were, she set her mouth and, cheeks aflame, stalked past. Unfortunately, she made the mistake of not averting her head as she did. A wickedly sparkling blue eye met hers... and winked.