Because no one wants to read that. No seriously. That's why.
No one cares that you got stuck in traffic, the dog made a poop in the living room, or that your kid made a funny face today. There's nothing more boring than that kind of site.
That doesn't mean you shouldn't write it. If it makes you happy, go for it. Some people just like to keep a diary, and if others want to read it, fine! However, you shouldn't expect people to come flying to your site in droves.
If you DO want to have a high traffic site with this format, it better be damn good. The writing and stories better be phenomenal. You had better have me falling off my chair with laughter each and every time. Then, maybe you have a shot.
Otherwise, just be happy with what little traffic you have.