I have a scenario for you: Your best friend of more than a decade (and counting) subtly hinted that she'd like for you to make her birthday cake on her birthday (of course). And you, being the wonderful friend that you are, may have said yes or pretended not to hear but really, you're already planning what flavor and design you'll be doing with the upcoming birthday girl's request.
Let's skip to a couple of weeks and into the day. The birthday. The day you'll be 'surprising' your best pal with cake.