You are the exception I think. Most interviewers care about the correct answer. Get it and maybe get the job. Fail and definitely don't get the job.
If the interviewer said at the beginning, "I don't expect you to solve this problem in the 40 minute nor to have an optimal solution. I just want to watch you write some code and hear the problems you foresee and how you'd solve them" then maybe I could relax and do that. But, generally the pressure is on "get this right in 40 minutes or you're rejected"
This is actually why I dislike these "coding interviews are useless" type articles. The issue has as much or more to do with bad interviewers than it does with the fact that it's a coding interview.
When I'm tasked with interviewing candidates and evaluating these basic algorithmic and coding skills, I have a 5-part problem (each building on the next, and only revealed when the previous one is complete) that is basically impossible to finish in the time allotted. I tell the candidate ahead of time that it's an ongoing problem that's designed to not be completable in the time: we're going to work through this problem and see how far we get. I've passed candidates who "failed" the actual problem, when the conversation and coding that were shown still gave me a good understanding of their capabilities.
If the interviewer said at the beginning, "I don't expect you to solve this problem in the 40 minute nor to have an optimal solution. I just want to watch you write some code and hear the problems you foresee and how you'd solve them" then maybe I could relax and do that. But, generally the pressure is on "get this right in 40 minutes or you're rejected"