Why Do We Sometimes Forget to Pray?

Some people forget about praying. Sometimes they remember, but later on, they will forget. Praying is an important communication to God. Mostly we chat with our friends and classmates but why do we forget talking to God? In an average person, we only pray 3 to 5 times a day. How about talking with our friends? Maybe it'll take more that a 100 times a day! So what I'm saying is that, talking to God is like talking with a friend! God is your friend! Your best friend! We should have a time in praying.