reddit is really a collection of sections pertaining to different subjects, called subreddits. As such, your experience on reddit will vary wildly depending on which subreddits you subscribe to, as they each have difference themes, rules and degrees of moderation. For example, /r/pics is pretty much a catch-all place for any midly interesting picture, and as such posts there probably won't lead to deep, insightful discussion in the comment section. However, if you swing by /r/askscience, you'll get a whole other experience. The moderators there strictly enforce the rules and quickly delete any off-topic jokes and memes, leaving only on-topic comments. /r/iama, where CmdrTaco posted, contains Q/A sessions from people ranging from celebrities to normal people with interesting stories. There is a huge amount of subreddits, so you'll probably find a bunch that are to your liking. /r/tf2 for Team Fortress 2. /r/nyc for stuff about New York City. /r/comics for, well, comic strips. /r/technology for tech news and discussion. There's /r/programming, /r/buildapc, /r/talesfromtechsupport, /r/football, /r/philosophy... There's a subreddit for pretty much everything. Of course, it also means that there will be a lot of subreddit that you don't care about. Just don't subscribe to them and you won't have to see those posts. A big part of reddit is tailoring your subreddit subscriptions to whatever you'd like to see. If you don't do that, you'll only get the default subs, and judging by your comment here I'd guess you're not happy with those.
So if you want to see if reddit can be interesting for you, my advice would be this:
First, go to this page, which lists which subreddits you'll see on the front page. If you have just created an account, you'll be subscribed to the default subreddits. Look at the posts in each one and decide if you want to keep seeing content like this. If not, click the "unsubscribe" button near the top of the sidebar and boom, it's gone. Just this step will generally increase you reddit experience greatly.
Next, you can search for a topic and look at the subreddits you find. If you'd like to see more, subscribe, then search some more until you feel that your front page contains stuff you're interested in.
That's pretty much it. I like that system, but as with everything, YMMV. =)