And the gates are very badly designed! The single-door design can't handle the peak crowds that go through them, and their 'beep' that confirms fare payment is

And the gates are very badly designed! The single-door design can't handle the peak crowds that go through them, and their 'beep' that confirms fare payment is a long monotone whine which makes it impossible to tell if you've paid successfully or the person next to you has, since all the gates are just constantly emitting a high pitched squeak. /rant