Expectation: Printing objects that manipulate the fabric of spacetime itself, bending reality and creating tesseracts in your living room.
Reality: Some black plastic chunks that took 7 hours to print and vaguely resemble the paperweight your kid made in 3rd grade.
The disappointment is strong with this one. That moment when you realize "4D printing" is just regular 3D printing but the objects can change shape over time (the 4th dimension), not a portal to manipulate the cosmos. Dreams crushed faster than a theoretical physicist's funding application.