I perform triage on my work Inbox several times a day, even on weekends. I have "read" your "important" message, but not really. I've prioritized it for real review on monday afternoon, after I take care of important issues (as prioritized by me). It's better for me and you if we just pretend this moment never happened.
Being in the dark sounds like a bad thing, but it's not. It's better for my mom to think that I haven't seen the long message she wrote on Facebook. After all: who knows what I'm doing?
In reality, I'm fucking around during this conference on the distraction that is Facebook, I'm touched by her message, but I can't exactly reply until tomorrow.