Why we have to think about it?

Now a question will come to our brain that why we have to think about evolution? We are good in our wants. But if we think deeply we may understand that, without thinking about evolution we can not describe many things around us. Such as –
--Why doctors advise their patients to complete the full dose of medicine?
--How much we have matched with the rats that scientist applies their thinks at first on them?
--Why there’s a different kind of look in all Human Being?
--Where we came from?
We have similarity with the Chimpanzees at about 98.5%, Rats 85% (not 100%). For these reason scientists applies their research on these animals. Each scientist describes evolution in different way. Some of them are concurring about this & some are different in their opinion.