God help the person who has to pick up after you, do refactoring etc etc. Not writing tests is unprofessional as it introduces risk. If code is being used by 1 person or is some non-critical internal application then fine. If it is being used by 1 million people to earn a living the people responsible should lose their jobs. I spend a significant amount of my time tidying up after people who don't write tests and leave a mess and it's a nightmare (but keeps my family fed, housed and clothed so...).