Riverwalk
Never mind reading the whole thread, some people don't even read the original post properly!
For example 'my 13 year old granddaughter is blah blah'....
Someone will then ask 'how old is your GD?' 
Some threads are very long so it's inevitable that things move on, and posters don't have time to read the whole thing.
I agree with Riverwalk and felice that it’s not just not taking time to read all posts, but original posts too. To me, it gives the impression of not being listened to, when, as well as the examples above, replies don’t reflect the original question. It’s not very helpful to someone who may be needing a wee bit of support.