The howling sound is caused because there is an infinite feedback loop between a speaker, an amplifier, and a microphone when the amplified sound from the speaker is received by the microphone. When you use a microphone in a room and get too chockablock to the speaker, you might hear the extraordinary high pitch sound.
The same thing can happen if you are an alcoholic. When you drink a lot of alcohol, you will get a hangover. If you drink additional alcohol, you feel that your hangover seems to be mitigated. Your brain will learn and remember "oh, to ease the hangover, it is better to drink more alcohol." Go back to the beginning of the loop.
Even a good habit can fall into the same bucket. When you eat healthier food or do an exercise, you get the better "feeling", which is not necessarily a better effect on your body. Your brain receives a good signal and remembers "it is better to do more!"
Addiction, bad habits, and good habits are a kind of similar loop but the important factor is controllability. I would like my kid to have the capability to predict whether this action can be controlled by himself or not once he starts with doing so.
Word of the day: chockablock