Moderation is key, really. Moderation and just keeping a base that no matter what happens you are going to be ok. Also not allowing these said substances to over power your ability to decide what is and is not socially appropriate. For example, the wizard was probably having and amazing time running around the polo fields, its when he decided(or the drugs decided) that wearing next to nothing was not enough that he got into trouble.
There is however the possibility you are one of the unfortunate people born psychotic or schizophrenic to a small degree and these substances then bring out those qualities. In that case, you are just crazy and tripping with 70,000 people.