The reason for the negative connotations is when it's used it also usually means "A system which nobody really understands", usually because of lack of tests an

The reason for the negative connotations is when it's used it also usually means "A system which nobody really understands", usually because of lack of tests and documentation. Maybe the high cost to modify it is working as intended in some cases (don't modify this project, start a new one). But when the business expects the legacy product to be modified, then you run into trouble.