Leaving your sister on read is disrespectful.
Jen has a sister who messaged about a problem but also has a serious a work deadline.
Jen wants to get her work done on time.
Jen replies quickly explaining her work deadline that she will make sure to get back to her ASAP.
Jen sees the message but ignores it and focuses on her work.
Jen's sister understands and thanks her for responding anyway.
Jen's sister sees that it was read and is upset after being ignored.