i usually try to make my first post on a thread about the first post that started the thread, basically i'll just read the first post, or first page if there are already a few pages, and say my opinion on the whatever the matter will be using the quick reply at the bottom, then i'll look through the rest of the thread...

but i'll admit i probably do jack threads sometimes but not on purpose, if i see an opportunity to make someone laugh, i will take it , and it's usually just a one off post.