Sleeping at work is definitely not my working culture, neither most of our Malaysian worker culture. It maybe yours working culture, but I'm sure it is not true for most of the people, although I can't say 100% but this is not our culture.
I've been working for more than 15 years, never a day I ever feel Monday blue, I may feel tired, feel exhausted, but once I touch on my work, all my energy back to me. Every day I feel lucky that I still got work waiting for me and I still able to do my task.
So, we deserve an apology from you and clear our charge.