I believe that trying too hard to be rational is irrational and perhaps self-destructive. That there could well be many different definitions of rationality or truth that are in some sense imcompatible without one being really superior (because we don't have meta-criterion to establish our criterions). When the cost is low, I think that behaving in a consciously superstitious way is rational because after all, we could be wrong about superstitions too (e.g. circumcision decreases venereal disease transmission).