Have you noticed?

Its driving me nuts ....... seeing how so many of us on here don't give helpful replies.
Have you noticed how a poster will ask a question, carefully explaining the relevant details, and smug sounding replies will come in by the bucket full detailing how that person always always does something that has nothing to do with the original question, and never has that problem.
For instance someone will ask about unblocking her sink, and she'll get answers on how to de-block the toilet or even a description of a 'little man round the corner' who is wonderful with blocked rain gutters.
Yet more will tell how she never ever pours anything down the sink and blocks it - its not helpful hearing how virtuous people are when you are struggling with a problem.
I confess I do it myself and often delete a reply before its posted because it sounds so self satisfied and not at all helpful.