I don't remember who told me, but when I first started cooking, someone somewhere said to remove the green germ of garlic cloves. I think they said it was bitter, but I don't remember exactly because I didn't question it: I accepted the green germ as being bad as a fact and moved on.
Let's back up a bit, though, and explain exactly what the green germ is. When garlic is young, the germ is pale, tender, and mild. As garlic becomes older, however, that germ turns green, grows, and, as many will say, becomes bitter. The Joy of Cooking asserts that garlic with a green germ is old and shouldn't be used. (Which I take to mean that it shouldn't be used at all.)
Related: Recipe inspiration
Ah, but it's not that simple (is anything?). Jacques Pepin was also taught to remove garlic's green germ. But, after some testing, he found that he liked the garlic better with the germ left in. Marcella Hazan also never removed the green germ. Her reasoning was, as David Lebovitz explains in his own green germ exploration, that "since it [the germ] was new garlic in the making, it was tender and not bitter."
Oh, but it's still not that simple!
In the same post, Lebovitz tested garlic and green germ-ed garlic two ways: raw, in mayonnaise, and cooked, in pasta. His conclusion: The mayonnaise made with the green germ had a disagreeable bite to it, but there was no discernible difference between the two cooked pasta dishes. (Lebovitz says he'll still remove the green germ in all applications regardless.)
The not-so-simple, simple conclusion: If you don't like the taste of the green germ, remove it. If you don't mind it, leave it in. And if you're using garlic in braises, soups, stews, or even roasting it whole, the germ probably won't make much of a difference anyway.
Do you remove the green germ? Let us know in the comments!