This has happened with you most of the times that when you sign in your account or get an online movie ticket, you get this recaptcha dialogue box, what is it and why does it wastes your time. I will tell you all about it.
Imagine that timings at which opening to get tickets start at 10AM and you start your computer and get some 2 tickets for you which took you 2 to 3 minutes and other people do the same. All the tickets for today has been sold now. So their are a lot of people left who wants to take the ticket for themselves. Their are some people who are good coders also. So they make code, through which the computer will automatically buy tickets for them in just 10 seconds. This is cheating man, so their came something called as recaptcha which Google liked and bought from its developers so that people can't cheat anymore.
So now you can tell your friends about this and they'll be suprised.