Isn't green curry mild?
It has heat. Coconut milk can make it feel gentle, but the curry paste is made with chilies. If you do not handle spicy food well, ask about the heat before you order.
Kaeng Khiao Wan · แกงเขียวหวาน
If you want a fragrant curry with rice, pick green curry. Green curry paste is stirred into coconut milk, then meat and vegetables are simmered in it. The richness of coconut gets a lift from herbs like basil. The pale green color can look mild, but it has heat, so if you do not handle spicy food well, say so when you order.

Behind the rich, smooth coconut milk, you taste the heat of the curry paste. The herb notes come through clearly, so it tastes quite different from sweeter, milder curries. Spoon a little curry and its pieces over your rice at a time.
Even with coconut milk in it, it is still spicy. Ask about the heat when you order.
Green curry is one of the signature dishes of Central Thailand. In Thailand it is eaten not only with steamed rice but also with noodles such as khanom chin, or with roti. On a trip to Bangkok, order a curry with the meat you like and eat it with rice.
It has heat. Coconut milk can make it feel gentle, but the curry paste is made with chilies. If you do not handle spicy food well, ask about the heat before you order.
Not necessarily. The curry paste or seasoning can contain animal-based ingredients. If you are vegetarian, ask not only about the meat but also whether you can eat the paste and sauce.
If you want to read more about the food and the regions behind it, these sources are a good place to start. Ingredients and recipes can vary from one restaurant to the next.
Sharing image credit: Takeaway · CC BY-SA 3.0