Does the brain really have infinite memory?

The function of the brain is so strange without it we are nothing. In class X, I read that brain has infinite memory but still, I wonder why I can't remember every single thing. According to scientists, all things are always stored in the brain but when we try to retrieve the information, it sometimes could not remember where it actually stores that information. This happens due to the failure of some neurological or psychological mechanism. Maybe the brain knows its defect very well so to hide it, it tries to tell us to recall less information as possible. That is the reason why we try to remember the summary of a chapter rather than the chapter itself. That is also the reason why we recall someone's character by his/her negative characteristics rather than his/her positive characteristics because a person has fewer negative characteristics as compared to his/her positive characteristics.