Why do I need to learn the Perfect tense?

If you stopped 100 native English
speakers in the street and asked them about
tense, one of them might give you an
intelligent answer—if you were lucky.

And
they would know nothing about aspect, voice
or mood.

Of
course, for ESL it helps to know about
tenses, but don't become obsessed with them.
Be like those native speakers! Speak
naturally!