Dandelion greens grow everywhere and provide a variety of nutritional and health benefits. But most people don't want to eat them, because they are very bitter. Most of the time I don't want them by themselves but I do enjoy them as an accent in other dishes, or sauteed with caramelized onions to create a milder bitterness. Occasionally I want the bitter taste by itself and eat them that way. Bitter is the taste of unsweetened chocolate, coffee, alcohol or tobacco. It can be very helpful in reducing cravings for those things.
So it's good to increase healthy sources of the bitter taste when someone is trying to reduce or quit those things. Though it won't do as good of a job at reducing the craving if a person who wants coffee or chocolate is actually just craving the sugar in them. Then you would also have to ramp up consumption of wholesome forms of the sweet taste.
Overall, I don't think we are supposed to consume a lot of the bitter taste, but we do need some. Unfortunately in most modern diets the only source is from more the more toxic substances I already mentioned. I think our lack of the bitter taste in our diet is part of why people are attracted to coffee, chocolate and tobacco.
We need all five of the tastes in our diet - salty, sour, bitter, sweet, and pungent. One way or another, we will seek out unhealthy alternatives, if we don't have an adequate healthy source of any of the tastes.
Pungent/ Umami (the 'sparkly' taste) - raw onions, raw garlic, horseradish, radishes in general, ginger, wasabi, mustard greens, are all examples of umami
Sour (tart)- comes from vinegar, sauerkraut, some pickles, sour apples, cranberries, lingonberries, and citrus fruits
Bitter - other wholesome sources are broccoli rabe, radicchio, chicory, arugula, endive
Sweet - can come from sweet vegetables; carrots, winter squash, cooked onions, parsnips, chestnuts, sweet corn, seasonal, indigenous fruits and berries
Salty - good quality sea salt or Himalayan salt, celery, sea vegetables, miso, soy sauce