You have to understand this: back in her school days, there
weren't any halter bras for her and her peers to sport to be able
to expose those tantalisingly-looking straps to attract the male
student population.
You see, she was just being jealous, so have sympathy, give her a
pair of the most sporty-looking pink halterneck bra for Teachers'
Day/her birthday/your graduation.
She'll love it and you too! 
