Simple:
* Don't underestimate the power of a good night's sleep.
* I underestimated how much work this project would require.
More Complex:
* The team's opponents underestimated their abilities, leading to a surprising victory.
* You should never underestimate the resilience of the human spirit.
* Despite her small size, she was a powerful force, and many underestimated her strength.
Figurative:
* The storm underestimated the strength of the old oak tree. (Personifying the storm)
In a question:
* Do you think people often underestimate the importance of kindness?
These are just a few examples. You can use "underestimate" in many different ways depending on the context of your sentence.