Let's see a screenshot of your facebook then. Feel free to blur out the names, but leave the inane peanut-gallery comments... I know they are there.
-Suntan
I don't think you understand. Some of us enjoy friends that make goofy comments (I am one of them!). If I didn't want the comments, I can hide posts from those people, or even remove them as a friend. You can even categorize them (family, friends, whatever you like) and view only posts from individual groups. It really isn't hard to limit facebook to posts that I enjoy, I have my own preferences that might not be the same as yours so it's not really beneficial to show you my page.
On the more serious side of examples, I am a musician and I am friends with many other musicians. FB provides the opportunity to advertise performances as well as the occasional performance opportunities friends might be offering. Networking is extremely important for me and FB makes things a bit easier for me job wise. Maybe this won't matter to you, it's just an example that those "posts" you don't find worth your time isn't the only thing facebook is about...(market place, share photos/videos, events, organizations, so-on...)
Same with Twitter. Tweeting one thing for a free download is only trying out a small PART of twitter. I actually use twitter (and Google+ actually) to follow a lot of mixed news (ESPN/Sports, Android, Apple, developers, etc). I also follow comedians as well, I do like some humor
I don't even really tweet much myself, but I do use twitter frequently.
Like Ricky said, if it's not for you then cool, don't use it. No reason to knock it though when you have only experienced the tip of the ice berg.