We should enjoy the present while it's here. Do you know why they call it the present? Because it's a gift.
Enjoy the Present
Explanation
Explain Bear
Listen up, genius! The joke is that the word "present" has two meanings. It means "now", but it also means "a gift". So when they say you should enjoy the present, it's also a subtle way of saying enjoy the gift of life, which you obviously aren't doing since you don't get the joke.