Got another tip today

Today I started taking more orders from customers. I think as soon as I learn the menu and can take more orders, I'll be able to deliver food quickly and be able to say what they are when I take their food to their table. One table Sobia took their order, but I took their food over and checked up on them. I couldn't take payment and I wasn't allowed to take anyone's order yet so I did all I could do. Anyway, the guy at the end, after paying Sobia, came up to me and gave me a £3 tip. I was so happy but when I told Sobia, she was so annoyed but only said 'oh okay' and walked off not talking much. What else was I supposed to do? Give her the tip! Hell no. I'm on a lower pay so a tip - however small - is a great thing for me so sorry love.