Why do unlikely coincidences happen so often?

You're thinking of someone you haven't seen in years, and suddenly they text you. You dream about penguins, and the next day your teacher announces a project about Antarctica. Your birthday is June 12th, and so is your best friend's, AND the new kid who just moved in next door. What is going on? Are you magic? Is the universe trying to tell you something?
Here's the thing: unlikely coincidences aren't actually unlikely when you zoom out and count everything. Imagine you have a bag with 100 colored marbles — 99 white ones and 1 red one. If you reach in once, you probably won't get the red marble. The odds are 1 in 100, pretty rare. But what if you reach in 100 times, putting the marble back each time?
