One good reply: "But I see you couldn't keep him interested..."
Bump for humor value
I don't think I would have mouthed anything. I would have asked her out loud if her mother is as trashy as she is. I remember telling a customer that her foul language is a disgusting example to her children and she's not fit to be a mother. She proceeded to cuss me out loud and threaten my life. Too bad. She demonstrated her glaring lack of education and manners and folks (including my boss) were high fiving me aferwards.
Public cussing is a big pet peeve of mine. Yes I do cuss sometimes but always under my breath and I never curse in front of my mother. Once I said a-hole and she asked me if I grew up in the gutter with vagrants. Enough said. Just like folks who wear shirts with cuss words on them, bumper stickers are designed for attention. Anyone with cussword stickers is an attention whore.
One I saw the other day said Barbie is such a B_____. I like you have a 6 yr. old who reads everything. She saw Barbie and started to read. Luckily the light turned green and the car moved before she read the rest.