Well, a lot of Jewish worship is communial. You're not just you the individual, you're you the member of the Jewish community, and certain things are either best or in some cases only done with 10 adult men or more, and in any case, a lot of rituals are considered better if done as a body.
I went to law school in Chicago, and I was away from my family around the holidays, so I went to a Chabad Seder, a Seder being a ritual meal and lesson that's done on Passover. I introduced myself to the Rabbi running it, and being somewhat educated, I made a pretty good impression, and he asked me to be kind of his assistant when running things, because there were going to be about 30ish people, and just passing out everything and keeping everyone together is something of a task. Sure, I was thrilled.
Come the night of the Seder, and I'm doing my job, helping him run things, and, because it's a Jewish holiday, eating and drinking prodigiously. By the end of things, I'm more than a little sloshed. We had finished all the ritual stuff, and we were just singing some old songs, because who doesn't like singing? There are several ones that seem to get sung at every Seder, Had Gadya, Ki'lo Na'eh, Adir Hu, etc. In what I can only imagine was because he was sick of the same ones over and over again, the Rabbi asks me if I know any Hebrew songs that haven't been done to death.
Keep in mind, I'm quite drunk. And the first song that pops into my head is a filthy one that a buddy of mine from college and an ex IDF guy taught me, about a rooster who really likes this one hen in the back of the coop, but by the time he's done fucking all the other hens, he's too tired to give her a good time. And I just launch into it, probably badly off key as well, and only realize what I'm singing when I'm about 4/5 of the way through with it and I can see this unbelievably stony expression on the Rabbi's face. It was awkward coming back the next night.