Gmail has your back
Gmail gets better and better, you can feel safe knowing that Gmail has your back; I was surprised while I was writing an email and when hitting “Send” a warning came up telling me that I mentioned in the email about an attachment but nothing is attached
And gave me the option to stop the sending in case I have to attach some files and I forgot. How cool is that ?!
This is a very common mistake that people do, if you write many emails it must have happen to you few times, you are saying that you attached some files but you forgot to attach them
Or on the other hand you might not be very happy to get an email with missing attachments.
Here is a screen of this feature:

On 13 February 2009 (Friday) at 23:31:30 GMT the Unix date will be showing exactly: 1234567890.
LONDON, England (CNN) — An earthquake shook Britain early Wednesday, causing damage to buildings and leaving at least one person injured. This image provided by the British Geological Survey shows the seismogram registering the earthquake at Market Rasen, England on Wednesday.