I just started a new job and asked my boss to order me a USB hub about a week ago (they will order stuff you need for work). A couple days later I discovered that the monitors have built in USB plugs. I started using those and then felt like I no longer needed a USB hub.
The USB hub came in the mail today, and I told my boss I realized I didn't need it. He said, "Ok, just make sure you need it before having me buy something". I apologized but I feel really bad now. I was thinking of making it up to him by buying him a small gift.
I don't know if that would be an overreaction or not. But I know how bad it feels sometimes when I feel like I get taken advantage of (maybe what he is feeling) and it might be good to make up for it.