I think you might often missed to attach file when sending email. But Google (Gmail) has its capability to detect any word “is attached” inside mail body. So you will get a warning like this :
Google Attachment Warning
Something useful from Google, good job! 
Categories: Internet
good job rom..
it”s now in english? oh mi god
*take google translate*
hahahaha..injih sakmenika ngagem boso kromo londo…