mouth to mouth

I've wondered before and I'll wonder again; how the hell do people think drink helps them cope with stress or difficultness and so on? Although my stress/tiredness coping mechanisms of walking lots, reading, looking at internets and playing guitar might not always help (especially reading or looking at internets after a long workday reading things and looking at numbers on screens) it's certainly a lot better than rinsing the brain away with shouting-juice.

The other thing I wonder is why there are two half-bottles here; surely one whole-bottle would have been cheaper?