There certainly are, very often, questions that the attorneys on my side don't want to ask me, because my truthful answer won't be helpful to them. We discuss that in advance. There is always the risk that the other side will see an opportunity.
Thankfully, opposing attorneys general have zero understanding of the science (chemistry, in my case) and they usually have too much of an ego to rely on the advice of their own expert as to how to how to question me.
The best attorneys I have worked with also ask me to help them formulate questions to pose to the opposing expert. Nothing makes an expert look more silly than being short on the facts and shading the truth.
Judges have mentioned, directly in their oppinions, how one expert (me) was more credible than the opposing expert. A billion dollar drug survived a patent challenge in this way. The opposing side said that a 1960s experiment must have produced a certain chemical substance that was later patented as a drug. Their expert swore that the experiment would have made the substance. I swore that it could not possibly have. I explained to the judge the mechanism of the chemical reaction and why the other expert was wrong. But... I also repeated the experiment, exactly, and looked for the alleged contaminant. I proved that it was not produced to any detectable amount, with a limit of detection of 0.1%.
That's not to say that I haven't lost cases. I have been on the losing side twice, the winning side four times, with a half dozen or so settled somewhere along the way.