'I painfully lack diplomacy skills and have zero ability of the stiff upper lip (and also very low tolerance for it...)'
Me too!! And like you i find it hard to keep myself in check when the pressure mounts up again. And i hate things being 'unspoken'.
Also in terms of perspective, its great you're thinking about that and its massively helped me in the past - and being a manager has really opened my eyes to why things that happen can be misconstrued or blown out of proportion.
Try asking someone you trust outside of work to give you their impartial opinion, but be open about the fact you think you might be being unreasonable - you're more likely to get honesty from them that way.
I have come across people who for a variety of reasons dont have that much experience in other workplaces and therefore have totally lost perspective. Its very easy to do so, especially in a high pressure environment where it just takes up so much emotional energy being at work.
To give you an example:
Perception from Person A:
'i've been allowed to sit by my mate (Person B) for 20 years and now im being told i have to move, yet other people are being allowed to stay where they are, why am i being singled out, this feels like bullying after i raised a concern about shift patterns to my manager'
Reality from the manager: 'Another member of the team (C) is struggling performance-wise and will benefit from being sat next to an experienced colleague, so the manager has decided to move them. Elsewhere, two other colleagues are very loud and disruptive when sat together, which they've been warned about, but have not done anything to change. The best way to resolve this is to move A inbetween them as she's more experienced and they wont want to disturb her out of respect, and move C next to B who is a great coach who loves to help out. For various reasons due to disability adjustments we cant really move anyone else without a lot of disruption, and it wouldnt be appropriate to fill A and B in on C's performance issues or the noisy twins behavioural ones, so we'll just say we thought a little shake up would be good to spread knowledge wider across the team'
In another company, person A would go 'oh ive been moved - thats a bit annoying as i love chatting to B but im there to work, not the end of the world'
But in an environment where you have a lot of other issues going on, very easy to think its about you when it isnt.
Im also guilty of gettting wound up by things that have nothing to do with me! If you see something REALLY wrong happen in front of you its hard not to get involved, but for a lot of things in hindsight i think... did that situation actually get resolved by me expressing my opinion or getting involved in the way i did? Probably not is the answer. Its helped me reflect on:
How i get involved, if i get involved at all, or if getting involved actually will help the person im trying to help or if i just hate the company so much im on edge all the time ready to fight another battle?