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You mean "Is it immoral."

Really, it depends on the secret. If it's something that may be affecting the lives of others in a bad way, and telling your parents would help the situation, (even if it gets you in trouble) then you should probably tell them.

If the secret affects no one in a bad way, and you just feel bad about not telling them, then it's ultimately a decision that you will need to make on your own.

Yes there are seceret's of everyone life and sometime the situation comes we cannot share the thing or the feelings to parents even so this is moral thing to share everything to parents.
If we are sharing our feeling o everyone just hey will feel like a dog always barking with us and the time comes they will slapped you even