Bad manners? Bad service?

Today I was at this hypermarket chain near my house. I was walking in one of the aisles when a hypermarket worker with a trolley load of things almost bumped to me while taking the corner. I had to quickly give way to her to avoid getting hit. Instead of saying sorry, she said in a very irritated manner “aiya!” Then when I was at the payment counter, the cashier punched in my purchases, I gave her the money, but instead of giving me the change right away, she held on to the money for a good 2 minutes while chatting with her colleague at the next counter. I said to her rather politely in Malay “saya nak bayar” meaning “I want to pay”. She heard me I am sure but continued to talk for a while, then put the cash in the cash box and banged it shut very hard and handed me the change in a rough manner.

My friend’s advice to me was to make a complaint. You don't pay for bad service.
But I suppose I am more of the conflict-phobic type. I hate ugly situations and I am not sure whether I am capable of voicing my complaints in a calm manner. Normally when I am angry, I will just keep quiet or just walk away. But it will be a long time before I patronize the place again!