I can't quite describe the wave of guilt that overwhelms me when my toddler says that.
I mean, it's funny at the time, when he's refusing a nap or to go out or something because he's "busy" but afterwards it strikes me that he's learned that phrase from me.
Similarly guilt inducing is when he toddles by and sees me clearly working away at something and says "Mummy busy", usually followed by him getting his step stool or a brush (depending on what I'm doing) and trying to help.
I don't want him to be two and aware that Mummy is busy, too busy for him. I want him to know that I'm always putting him first.
At the same time, I want to be able to do the washing up, sweep the floor, package up some item to be posted, clean the bathroom or write an important, time sensitive email without a tiny hurricane ripping through it all. I would also feel guilty about spending every one of Small's waking moments keeping him at the very centre of my attention span but making him live in a filthy home.
The worst of it is that he's at that age now where all he wants to do is help. "Help Mummy! Help Mummy!' he cries as he runs over to my assistance. Sometimes I'm washing up and am summarily shoved aside by him pushing the step stool over (his 'ladder') so he can take charge of the brush and poke it at the dishes while running the taps. Or the hoover, operating the hoover causes Small to be consumed by two contradictory impulses, one to make the horrible noise stop and one to grab it off me and shove it along the carpet himself, except he can't because the suction is too strong for him. Ah now, you're thinking that the solution is to switch it off and let him play for a bit before distracting him with something else and carrying on aren't you? Wrong. He doesn't want to play with it, he wants to hoover up. When he wants to play at hoovering he has a toy one he uses for the purpose.
It's little wonder the words 'sweetheart, please, Mummy's busy' really. It's still a icicle in my heart when he repeats it back though. Must be a Mum thing. Or a Not Very Good Mum thing.