I often read the expression “would of” used instead of “would have”. Each time I read it I get annoyed so I googled it and found out -as I expected- that it is an incorrect way to say “would have”. Now, there are a lot of brilliant slang words/expressions, so my question is, why do people use this one? It’s so annoying to read, stupid and clearly wrong, it is pointless, why did they come up with this expression?
Edit: I don't think my question is a duplicate as I didn't ask how can somebody use it (since I know it's incorrect and I know that I can use it with commas giving it a different meaning) but I asked why and how people came up with this expression.