to go to the trouble of
Expresses doing something deliberately despite the effort or inconvenience, often implying it wasn't necessary.
わざわざ means 'to go to the trouble of' or 'to make a special effort to do something'. It emphasizes that the action was unnecessary or extra, and the speaker often feels it was too much. It can be used for both positive and negative situations, but it carries a nuance of 'you didn't have to' or 'why did you bother?'.
In conversation, it often appears with expressions of gratitude or mild complaint. For example, if someone brings you a gift from afar, you say わざわざ to show you appreciate the trouble. On the other hand, if someone goes out of their way to criticize you, you can use it to express annoyance.
It is a common word in both speaking and writing, but in polite speech it is often softened with phrases like わざわざ~していただいて (for someone else's action) or わざわざ~する必要はない (no need to bother).