Unfortunately the NHS as it is today is set up to make people like this. Almost everybody starts off with the best of intentions, but the NHS relies on the generosity of its front line to constantly go above and beyond what their pay grade and even physical and mental ability allows. Every single person has their limits when it comes to how much pressure and stress they can take, and when you are used to seeing patients suffer because the care is just isn’t provided for them (not through malice usually but through lack of ability/staff) you become hardened and desensitised in order to stop yourself from having a complete breakdown. During covid, I saw even the most strong, talented, caring and amazing nurses completely crumble and their mental health suffered. Many people have had prolonged periods of time off due to stress/depression/anxiety, I’ve even known people literally start to suffer from auto-immune disorders due to the stress. The most important thing is to recognise when you have become like this and take a step back, but that isn’t always an option for people who have families to support.
(Apologies, off topic).