Q&A

If I assume you're happy to use other colours then you could use another colour as an accent colour that makes you feel happy whenever you see it. Choose textures for the black that you enjoy touching or looking at. And I've noticed that plants look amazing against black so you could choose one really stunning plant to sit in contrast to the black. A fun or quirky element in the room might help too, like a really unusual light or a sculpture.

clever, funky lighting, perhaps tiny spots or filaments. another bold colour on a feature wall or a metallic wallpaper.
pale floors, and coloured furniture. Amusing personal photos in funky frames to lighten the mood

these two guys have pretty much covered it. textures for various reflecting effects, lighting for variations of tone, accent colours, shapes or images to break up the expanse of black. i guess i didn't really need to bother...oh well. always like problem solving ...