One of the parts of Jewish religious observance that I'm the most drawn to is Shabbat, the sabbath. And yet being Shabbat observant (shomer shabbat/shabbos) in an Orthodox sense would be very difficult, not least because there are so many commandments that I do not know!
Shabbat starts Friday evening and continues until after sunset on Saturday, in accordance with how days are reckoned on the Hebrew calendar. During Shabbat a whole host of activities are forbidden, including but not limited to: working or causing your animal (or slave) to work, starting or putting out fires, turning on or off devices that use electricity (by analogy with fire), carrying things across property lines, traveling (more than a certain distance past the edge of town), handling money, and so on. There are thus a lot of restrictions that cannot be avoided and some that can be - by setting timers to turn things on and off automatically, one can avoid turning the lights on and off, or by living within an eruv, a sort of fictional property whose edges are defined by temporary barriers of sorts, commonly wires attached to telephone poles, one can carry things within that area. And any of them can be broken - is required to be broken - in order to protect human life. But these laws are a large part of why more traditional Jewish communities tend to be concentrated to some extent around a synagogue.
All of this doesn't have that much relevance to my life - I circulate in progressive communities (Reform, Reconstructionist, and similar), I don't believe in God, and in practice I don't observe any of the commandments strictly, although I try to avoid using the computer, the television, and the telephone on Shabbat. Furthermore, I am not technically Jewish, either by the traditional definition according to Jewish law or by the Reform definition. So why does this interest me? What exactly do I like about it?
I like not feeling the pressure to be productive. I like getting advertisements and phone calls out of my face, and escaping from the sensory overload of a modern, plugged-in life. I like taking my time and doing things slowly. I like reading, one of my major Saturday activities. And I enjoy the ritual. Lighting candles reverently, ritualistically, with a blessing (here in Ashkenazi/Eastern European pronunciation), feels holy to me, whatever that can mean to an atheist. I like havdalah as well, but I rarely get the chance to participate in that. I like the synagogue services, welcoming in Shabbat in the evening service and the Torah service Saturday morning, especially the chanting (or here's some cute kids chanting). I enjoy the camaraderie over snacks or a meal afterwards.
And I suspect that if I was more strict at least about the restrictions I try to impose on myself, I'd enjoy it even more. But this is something I waffle about every week.