Who doesn't love a surprise in their treats? Of course, when that surprise is a happy treat itself, not, like, a worm or something. Finding a heart in your cupcake is like finding a love note. It makes you feel special to know that someone cares enough to make a gesture.
I bet a teacher would appreciate a cupcake that looks like an apple even more than an actual apple. Yes, they are the pillars of society, but everyone needs an unhealthy treat now and again. Plus, maybe it's some sort of apple spice cake, that's not so unhealthy right? I'd even eat that!