Your colleagues ARE
enthralled by English; it is their chosen profession.
My 'ex' worked at the United Nations. I suffered through dinners of diplomatic jargon for a
decade.

You are correct, but I feel you may have missed my point. My ex-wife also had to deal with my never-ending drivel about work during dinner.

You've been here 10+ years and have no doubt worked alongside countless Chinese English teachers who ARE enthralled by English.

As I said, I have all the time in the world to help and assist them with their questions about English and how it works, however, there are certain contexts where there simply IS 'no why' when it comes to explanations in grammar or word usage. Maybe the reason has long since been forgotten, or perhaps nobody cares anymore.

Etymology is a hobby of mine (sad but true), so I love it when I'm asked why we say, for example, 'six o'clock'. The phrase 'o'clock' used to mean 'of the clock', but to cite my previous example of why we say that cows are IN the field, yet footballers are ON the field, probably has a reason that's long since been forgotten.

Chinese English teachers who persist in their quest for a reason 'why' we say or use something in English that we can't explain, drain me.

I am by no means condescending, nor do I belittle them. In fact, I welcome their enthusiasm. However, sometimes English is, well....'English', and some things defy all explanations, therefore the typical Chinese 'No Why' applies. My feeling is that 'Pig Dog' has also experienced the refusal to accept the 'No Why' response, hence my agreement with him.

What I find most annoying is the incessant 'why'. I have no problems assisting my Chinese
colleagues with their English, but it's the 1000-word explanations as to 'why' that gets
boring.

Why do we say 'The cows are IN the field, yet The football players are ON the field?'

Anyone who wants to engage in conversations like this over dinner every day should ignore
your warning.

Native language speakers are rarely fascinated by their own language. Your colleagues ARE enthralled by English; it is their chosen profession.
My 'ex' worked at the United Nations. I suffered through dinners of diplomatic jargon for a decade.
The solution is to find a spouse that shares your passion outside as well as inside the bedroom.
[edited]

Whilst some may have labeled you as a 'Chinese-woman-hater', what you are warning about here is actually 100% true!

Even during my 2 short years of working here, I have seen this scenario happen at least 4 times already, EXACTLY as you have stated.

What I find most annoying is the incessant 'why'. I have no problems assisting my Chinese colleagues with their English, but it's the 1000-word explanations as to 'why' that gets boring.

Why do we say 'The cows are IN the field, yet The football players are ON the field?'

Anyone who wants to engage in conversations like this over dinner every day should ignore your warning.