Why not?
(I get that some people have legitimate anxiety issues when placed in a situation where they're being judged and have to perform rationally under pressure. Hell, I face this every day when I think about getting customers and delivering to them. But these are worth working through on their own: there are many situations besides interviews where you will be forced to make clear & correct decisions under time pressure and are being judged on the results. The key is to focus on the thought process, not the judgment: the interviewer is irrelevant, if he doesn't like what you do go off and find another interviewer.)