I find that self-checkouts are helpful for people who feel sheepish about buying certain products, or certain combinations of products. I bet there's a measurable uptick in sales of feminine hygiene products, condoms, constipation and diarrhea medicine, and other "embarrassing" products in stores that add self-checkouts.

I used to feel sheepish buying things for my girlfriend but I realized it's not bad for people to think you're a good partner. So instead of sullenly buying the hygiene products, I say go all out. Throw in some generic Midol and dark chocolate. No one will criticize you.