* Lifting the box: This requires you to exert a force against gravity to move the box upwards. This is work because you're applying a force over a distance.
* Walking at constant velocity: While it might feel effortless, you are still working. To maintain constant velocity, you must overcome friction (between your shoes and the ground) and air resistance. This means you are applying a force to counteract these opposing forces.
In physics, work is defined as force applied over a distance. Even if you are moving at a constant speed, you are still applying a force to counteract other forces and maintain that motion.
