Are you friendly to strangers in your travels?

I go to the check out line at Publix earlier. There is a mother and daughter ahead of me. About late 50s and late 30s in age. The mother sends the daughter to grab some milk, she hurries past me and then back, she apologizes sheepishly. I smile and say, It's alright. Try being me for a while, I'm in everyone's way. (being a rather tall and wide person)

They had a small shopping basket, abandoned on the conveyor belt, which I offered to return. More for the cashier than for them.

The mother shot me this suspicious side eye. I wondered why.

It sucks that a person has to extend reasonable suspicion to the smallest things. You never know what someone is after.