Moving Supplies at U-Haul

Guy at the desk was rude. I was waiting in front of the counter for 5 minutes while he was typing away at his computer, finally I asked him if I could check out, he claimed he was waiting for me! I was literally standing in front of the counter, he didn't even look up at me, so I figured he was helping another customer so I started looking at my phone. I guess he wasn't? I guess he was just...waiting for me to actually say I wanted to check out because that wasn't clear from the way I was standing at the counter with things to buy? And instead of just apologizing, he keeps laughing at me and telling me I should have spoken up. I was trying it to interrupt!