Yes it affects them.
Judges are pursuing their vocation as a career and there are career paths within the judicial system just as there are in every other career. Screw up too many times and your career ends at your present level.
Judges are also professionals and most take professional pride in doing their jobs well. Having a decision overturned is professionally embarrassing.
As a matter of public policy, there is no sanction that is directly applied to the judge otherwise judges would be too cautious to make decisions. Anyone who makes professional decisions will get them wrong from time to time - they generally are not punished.
That said there are judicial errors that stem from making the wrong judgement (so to say) call and judicial errors that stem from royally screwing up. The former are far less damaging than the latter. For an example of the former, a judge is applying a relatively new statute for which there have been no other decisions and interprets the legislation in a reasonable way but one the appeal court disagrees with. For an example of the latter, deciding the matter on a basis which neither party put before the court and which the judge did not draw to the parties attention during the trial - as a common law country, the New Zealand legal system is adversarial: the court exists to decide the dispute between the parties on the basis the parties argue, not to go on a "frolic of its own".
In addition, appeal courts can only overrule a decision if the judge has made an error of law, not if they have made an error of fact. A judge is allowed to be wrong about the facts but not about the law. In practice, the distinction is not trivial.
In a jury trial, the jury decides the facts, the judge decides the law - appeals can only be on the basis of what the judge did, not on the basis of what the jury did (barring egregious misconduct by the jury). In a judge only trial the judge decides both but an appeal can only be on matters of law.
