Q: Some children often say I don't want to play piano or gym is boring. How far can a parent I push to continue and when should let drop?

When it comes to activities that are mandatory at school, you’ll have to kindly but firmly insist your child participate to the best of his or her abilities. Not everything in life is enjoyable and you can remind your child that this will help build character and help them endure things they are less than enthused about when they’re adults.
 
As for elective activities, keep these things in mind:
Choose extracurricular activities for your child that they like
You might like playing the piano or think it’s a great talent for your child to pursue, but if they don’t like it, it feels like torture to them. Listen to your child’s interests.
 
Don’t push your interests onto your child
Even if you dislike the activity your child likes, be encouraging. This is something that interests her, not you. Be her biggest fan at whatever she does.
 
Don’t let them give up easily on their dreams
Your child may get discouraged if she fails at pursuing her interests. For example, if she plays on a sports team, maybe she didn’t do well at her last game. If that’s the case, remind her that we can’t win all the time and that if she loves it, it’s worth going for.