Today my boss told me to work more properly, because the massive feature I'm working is only halfway done.

Well thank you very much, obviously it's only halfway done yet. I'm responsible for the backend and the development for the frontend started today, by another guy who was working on another stuff until now. And I'm pretty sure we agreed that I will only do the backend...

Thanks for the uncalled critique. Great way to make me feel like my work is not appreciated. This motivated me very much to work the whole on the integration.