That was a recent question from a client who questioned my valuation of her case. In fact, the opposite is true. On both sides of our cases, it is important that the opposing counsel recognizes that you know what you are doing and are able to pursue a case diligently to the end. We may not love the person on the other side, but I usually have very productive second or third cases with opposing lawyers once I have gone to settlement or trial against them. Being nice to opposing counsel does not change the valuation of the case. The case is the case. It may be nice if you like the other lawyer or respect them but it does not change the case value.
When both sides respect their opponent, then at least there is usually agreement on what the case is worth and what it could settle for. Then, the only trouble is the respective clients and their valuations.