In Hostile Opposing Counsel Expert Communications.com writes:
If the attorney spends most of the deposition attacking how much money you make as an expert witness or how you testify more for one side or the other, or is extremely obnoxious and aggressive, just remain cool and calm. You have already won the case and that attorney knows it all too well. His only hope is to get you crack and say or do something stupid. Like you said, these tactics are primarily in depositions where they can’t be “seen”. These kinds of tactics are rarely used in front of a jury because the jury would see them for what they are. In addition, while you can’t always depend on it, judges may limit some of these theatrics as your client attorney may object to the witness being abused.