2) Human beings announcements
Most of all at Cardiff Central, where you get that irritating shouty "not for passenger use" man deciding to negate TfW's entire Welsh language policy by interrupting the Welsh-first announcements and shouting exactly the same thing several times in English only in a thick Cardiff accent. That guy definitely belongs in Room 101, or failing that a ticket hut in Coryton or one of those branch line stations.
Whilst we're putting Cardiff Central's staff in Room 101 or ticket huts on branch line stations, those pointless customer-be-damned orange bibs on the Valley Lines platforms are ripe candidates for redeployment.