The BART gates are a good example of design gone wrong. The gates were designed to be operated from both directions, one could use the same gate to come in to a BART station or go out.
But in reality most BART stations operate with half the gates working in a single direction. The gates flash not available either on the inside or on the outside.
I assume it was confusing as people would try to come in and leave from the same gates as people don’t tend to think much when they are rushing to catch a train.
I can see the reason for having it operate in both directions - the trains arrive and leave at different times and hence passengers are moving either in or out. But since BART has increased frequency over the years, bidirectional BART gates are a hindrance.