No it's my choose if I wanna be helpful and we respect people not for them for us. I feel good helping without a thank you because these people weren't raised like me and they need me to help them they would one day open their eyes and maybe be the same. Could be their were busy texting with iPhone !!! ( joking)
I DO get offended if a cashier doesn't say 'Thank you' after I've paid for my purchase! It's just plain rude for a cashier to say 'There you go' or something similar. It reflects bad parenting. I can spend my money anywhere, if I don't get a Thank you, I shop elsewhere, it's my choice.