poeple's behaviour

Because when the money gets finished, the lifestyle that the other person was originally responding too changes drastically. Start rich, get poor quick, and loose the girl. Or guy.
Thats why you should always consider people close to you in this respect, the old adage " would I want to be stuck on a deserted island with them". If the answer is no, then enjoy them until the money runs out again.
Take care.

Here's a corollary:

The steamy extra-marital American scandal involving American teenager Amy Fisher and Italian-American married man Joey Buttafuoco which resulted in the murder attempt of Buttafuoco's wife was widely publicized in the media.

Is this because a gossip-anxiety Hollywood (USA) movie such as "Celebrity" (1998) reminds us of prosperity?