Namaskar everyone,
This is all about modification. You can modify to make things easier, but you can also modify to make things difficult.
For example: Ardha Chandrasana (half moon pose), you can make life easy with a block for the lower hand. You can also make it difficult by not touching the floor at all. If you want more difficulty, fold the extended leg back and take hold of that ankle with the lower hand. The top arm is still extended up and the gaze is to the sky.
If it is still too easy close your eyes or do it on roller blades.

There is always a challenge for students who claim to be bored. The sad thing is they will not be satisfied in their practice of Yoga, because it takes a lot of ego, and bad manners, to tell a yoga teacher that you are bored from his or her class.
In effect you are wasting your time with an egotistical student. Maybe they should join a martial arts class. After a few punches in the face, they will never be bored again.
Peace,
A.S. Kumar