What is the most welcome expression?

Can you elaborate on what you mean by 'the most welcome expression'? Are you referring to a phrase or sentiment that is universally well-received and appreciated? Or perhaps you're asking about a specific context where a certain expression is particularly favored? Understanding the context would help me provide a more accurate and relevant answer to your query. Additionally, it's worth noting that what's considered 'welcome' can vary greatly depending on cultural, social, and individual factors. Therefore, it's essential to consider these nuances when determining the most appropriate expression to use in any given situation.