Other Southern examples...
No trains to or from Brighton (or any station on the BML South of Three Bridges) serve Redhill between the weekday morning and evening peaks, which is frankly bizarre, and yet for some reason it is felt necessary to provide a metro-frequency service to and from Horsham and two trains per hour to Bognor Regis.
Merstham has no direct off-peak service to or from stations from Redhill to Tonbridge, but otherwise shares an identical service with Coulsdon South.
Earlswood and Salfords have no winter Sunday service. I've never really worked out why not. It might be to do with saving a couple of minutes due to possible wheelslip in the winter, but there's hardly a lower demand for trains in winter months in that area and it's inexcusable to reduce a service for several months on the basis that the trains can't cope with the weather - this is Surrey, not some sort of Alpine retreat! Severe weather conditions should be dealt with as and when they occur.
Faygate is just a bit unusual, but does now have a bit of a better service.
North Downs Line services occasionally omit all stations between Guildford and Reading. Once or twice a day on both FGW and XC (well, on the only XC services, that is).