First of all I must say I find this piece to be exceptional. Very creative and original, a concept that clearly pops out and is helped by a minimalistic perfect execution.
It's very clear and very easy to understand, and this is its first perfection.
As great things of this design can be easily seen, I'll do my best to point out the things that, in my humble opinion, can be corrected, although what I'm seeing is a small jpg version and I may be confused by its size at some points.
First of all, I suppouse (because I can't clearly see it) that the words "ON" and "OFF" are made out of cofee beans. And I'm not sure (for the size), but in the first F of the word"OFF" there is a part that fades and it seems an error on masking. But, as I said, I might be wrong due the size.
On the other side, I think the terms should be put upside down. The word "ON" is mainly understood as possitive, but its placed on the bottom of the piece, with is considered to be the "negative" part. It is also on the darkest part of the background. Although it is true that some machines have the "ON/OFF" positions ordered this way, I think in a piece where the message "coffee makes you be in the ON position" is intended to be read as possitive, should be inverted, in a way that "ON" can be unconsciously undestood as "positive": on top and over lighter background.
I hope you find this critique useful