Liking involves different circuits in the brain, and uses the H&N chemicals, not dopamine, to send messages. In particular, liking relies on the same chemicals that promote the long-term satisfaction of companionate love: endorphins and endocannabinoids. Because opioid drugs such as heroin and OxyContin scramble both the desire circuit and the liking circuit (where dopamine acts and where endorphin acts), they are among the most addictive drugs there are. Marijuana is similar. It also interacts with both circuits, stimulating dopamine as well as the endocannabinoid system. This dual effect leads to unusual results. Boosting dopamine can lead to enthusiastic engagement with things that would otherwise be perceived as unimportant. For example, marijuana users have been known to stand in front of a sink, watching water drip from the faucet, captivated by the otherwise mundane sight of the drops falling over and over again. The dopamine-boosting effect is also evident when marijuana smokers get lost in their own thoughts, floating aimlessly through imaginary worlds of their own creation. On the other hand, in some situations marijuana suppresses dopamine, mimicking what H&N molecules tend to do. In that case, activities that would typically be associated with wanting and motivation, such as going to work, studying, or taking a shower, seem less important.