Without incoming connections, you could never receive emails, view websites, etc.
Really, you should learn to relax and enjoy your Mac. You don't have to worry about malware and security like you did with Windows. You don't have to run 3rd party apps to "clean" or "maintain" your Mac. Just use it and enjoy the freedom of not having to "fiddle" with it to keep it running well. Surf the web, exchange emails, chat, listen to music, edit photos, watch movies, play games.... use your Mac for what you want. It will take care of itself, as long as you don't do anything out-of-the-way foolish.
Probably the best piece of advice you could get at the moment.
Lets take a look at where you've got to:
Firewall turned on and stealthed.
No need for antivirus, sorted right?
No need for maintenance 'cos it does it itself.
Battery calibrated so that's healthy and ticking along.
A basic understanding of Disk Utility and partitions.
Getting used to Word on a mac.
Preview sussed.
Don't misunderstand me, this post is mean't to be funny, clever, sarcastic or any of those things, I'm just laying out where you've got to in the last week or so.
Take GGJ's advice, chill down a little, let yourself digest what you've learned so far and feel confident with it.
I like to follow the security threads because it interests me, has done ever since I've used computer systems, Windows, Linux or Os X, hence the question to Munkery, but in the meantime I'm concentrating on learning Iphoto and getting to grips with my digital camera (I've had it 2 yrs and still struggle with it

) and, oddly, learning to play the penny whistle (wait 'til I stick that one up in a Garageband thread

I'll integrate it into my mac use somewhere if I try hard enough)
You've got the basics sorted so as GGJ is quite rightly saying, don't forget to enjoy your mac.