Some people may use incorrect English and grammar is to shorten down sentences. Mr.Waugh’s example was in our school we say going to the docks as we know this means to go sailing. This would make it an idiom as only we know what it means others would not understand. Some people that use these terms may not even know as they grew up hearing them as normal. It is not that people don’t know how to use proper grammar. They speak properly to teachers all the time. We aren’t trying to impress our friends with our great English skills we are only trying to get our point across.
An example of an idiom in our transcript would be “my selfies get th girls”. Not everyone would understand that this means attracting or going out with someone. We would use this as in a group we understand what this means so it would be acceptable. People who do not understand though probably are not to close to us. It is also making girls sound like a commodity as you are talking about them as they are objects to acquire. In standard English it would sound like the girls have no power in what is actually happening.
React!