I like being able to see how things work. Windows is much more "the magic box that does computy stuff", where as in linux, even if you don't understand it all, it is there for you to see. Immersion is great for learning, and Linux organizes things in a good way to learn anything and everything you want. Windows trains you to click the mouse when a window pops up.
BASH, as others mentioned, is a wonderfully powerful language that has completely changed the way I work with my computer since I made a complete switch years ago now.
But personally, I love and live Gnu/Linux for cultural reasons. Sure, it is more secure, faster for near all tasks, but would I switch from a community of people that believe that the purpose of information is for it to be shared to paying someone that believes I should be in jail if I try to understand how things work? Hmm... no, doesn't really appeal.
I guess I think of Windows as a restaurant with really good food, but really rude service, and while you are reasonably satisfied with your experience, you can't help but notice the health department makes an uncomfortably large number of visits. But if you are careful, and have a lot of money, some of the best chefs in town offer their dishes here exclusively.
Linux is more like a farmers market filled with chefs whose greatest joy in life is for you to share their food and ideas. There is no limit, and everyone welcome. You can have all the food you want for free, and there seems to be this kind of rule that if you bring food, you are supposed to tell people what you put into it. If you use other peoples ingredients or change someone else's dish, then you must tell people what you put in it, and where you got the recipe from.
So people ask where to eat. Well, I think we are all really used to and understand the restaurant model, and paying ala cart. We even got special toilet paper every time we get food poisoning. On the other hand, there is an orgy out in the wilderness where they hope you know how to cook so you can share and play, but even if you don't know how to cook, or even know what a frying pan is, your still welcome, just be mindful the conversation may just be a little different then what you are used to.
So know what? I don't really care if that other place got the latest iron chef. Its expensive, and he usually never shows up anyway. They keep changing everything around every time they move, and make you keep buying things you already paid for. Not to mention there is a door charge before you even get any food, but that is usually part of the package deal anyway.
So maybe sometimes the food gets better, or even really amazing on a rare occasion. Maybe the food gets cheaper every once in awhile. If you are really lucky, maybe they fired that waitress that kept spitting in the food. That's wonderful... but know what, while I thought I was initially tempted by the free food and dreams of being a chef, I've found something of a community.
But it is nice to know that in addition to the great community, the food is actually better, even if you can't get everything out there.