You are known to have a very generous spirit, and today you need to extend that generosity toward how you constructively criticize people. Someone is not putting out the quality of work that they are capable of: and it's up to you to help them understand this. Don't be too harsh about it, just say what needs to be said and give them a very generous benefit of the doubt. They need you to be honest with them, but they also need you to be careful with them.