What causes selfishness in adulthood?

Hi !

first of all , sorry if do English mistakes.

Some adults have known , depends how old they are, times where life wasn't easy.
For some youngest, it was quite easy to get a jobwhich isn't nowadays. 
If you get fired at forty, it isn't so easy to find a job.

I think as well that, while technology, electronic and so on was on constant progress, people stopped thinking about what was happening around them.

It was as a race who would gave the last it- thing
obvious
USA is a large country (where I don't live) and I think it's not so obvious to realize what's happening in other countries.

All adults aren't selfish, but those who are  , in my opinion)  deem to be like in a bubble, tying to protect themselves and their family as if they was no other solutions.

I guess (and hope) they're just scared of what's happening in the world today. And instead of acting, they just withdraw into themselves and so become selfish. No one else counts. They just can't help thinking about themselves.

I'm not sure it was so before

And fortunately, selfishness doesn't concern all adults !!

hope I gave you some ideas !

What sisters? is it in a story?

Because greyhound is a type of dog and shark is a type of fish