Music can change a persons mood completely. When a persons sad or nervous they can listen to their favourite song and all of a sudden your in a much better mood. Music can even make you sad. If its a very beautiful song it can make you cry too.
Caffeine, found in coffee, tea, chocolate, and colas, is a stimulant. It can cause anxiety and insomnia. It can also make you feel jittery or restless. Drinking too much can certainly affect your mood. It is also a diuretic, and can make you feel more thirsty!
Your Blood Alcohol Content (BAC) is affected by the amount you have had to drink, food you have eaten that will slow uptake of alcohol, and the time since you consumed alcohol. Your body mass will also affect your BAC, since a larger person has more body. Your mood does nothing for your BAC.