I know, some will find it ridiculous, but today I have had this experience with a sample of the dirt-cheap 2012 MGH 1205 "Menghai Green" Brick I received for free from puerhshop. I am sure there is no old tree stuff in this brick, and it may contain some plantation leaves. Nevertheless, the power of this tea is overwhelming. It is totally "aggressive, in your face, and long lasting": I have had 21 steepings from it (many immediate ones, and the last one only 2 minutes), my personal record. It nearly gave me a caffeine rush, something I have never experienced before from a tea. As for the taste, it is rather simple, but thick and deep.