There's nothing like a nice, big bowl of cereal to start your day. That is, unless you're pouring cereal into a bowl only to discover that there's not enough to fill the bowl. You're pouring, and suddenly, nothing. The flow of cereal stops. What's next?
Do you throw out the portion of cereal in the bowl and start afresh with a different cereal?
Do you eat a smaller portion than normal?
Do you find something else to eat?
Do you mix the already poured cereal with another type?

You could toss the cereal in the trash, but then, what kind of person does that make you? I'll tell you. As soon as someone has not met your expectations, you toss them aside and look for someone new. Jerk.
If you eat a smaller portion than normal, you'll be hungry later. Possibly, and probably, before lunch. And then what are going to do? Sit at your desk and eat pencil shavings? You could, but the side effects are not entertaining. Trust me.
If your lack of cereal problem coincides with a lack of milk, then you're really up a creek. You've got to find something different. So you turn your back on the cereal, and find a bagel or a donut. You probably talk about your friends behind their backs, too. Jerk.
Mixing: No. Not ever. You're sick just for thinking it.