What compels you to open up a thread and post?

[yo_john117]

Millenium said:

If it's a user I recognize and have valued their threads/posts in the past, I'll be more likely to post in it.
If it's a thread about a topic that interests or concerns me, I'll be more likely to post in it.

I open threads mainly with the goal of inspiring friendly yet interesting discussions.

Or I post in threads to answer a question, like this one.

This. Also I like the occasional debate so if I see something I think is ridiculous or untrue I'll probably quote the guy.