You may be having a bad day, if on the way out the door, your 2 year old let's the expensive indoor cat out. And as you run down the stairs in your high heels you yell "dammit" loud enough for the neighbors to hear.
You may be having a bad day, if once outside, you have to chase said 2 year old down the driveway and snatch him out of the road while yelling to your daughter, "we need to catch the grey piece of #@$%"
You may be having a bad day, if you get to the supermarket and realize that you forgot to pack your daughter's lunch, so the $1.50 in cash you scrounged up won't be sufficient to purchase the hard candy (cough drops not being allowed at school) and a lunchable.
You may be having a bad day, if while walking through the supermarket, you look at the woman who is approximately your age, maybe a bit older, calmly shopping in her name brand workout gear (the gym is just next door) and want to strangle the life out of her for her child free, healthy, and peaceful morning.
I'm not an expert, but if those things happen, you may be having a bad day!