I'm tempted to reply that, if impacts can be negative and riots can have epicentres, lacks can glare; however, as I consider the first two examples to be nonsensical, I must concede defeat on the last one.
Introverts unite! (Separately, in your own homes.)
And what does "Ni h-eibhneas gan Chlainn Domhnaill" mean?
It's a hugely important truism and means, "It is no joy without Clan Donald". It's the first line of a wholly impartial poem praising the MacDonalds, and was written nearly five centuries ago by someone who wasn't in the least sycophantic or toadying, but who, by pure chance, was a close friend of the chief of the said clan and who depended upon him for patronage.
Flavourful is commonly used in American English, now simply know as "American". I was recently told, "I only speak American". Or even better, for a while Audible.com offered English and British English. Thus claiming the supremacy of "American". Flavoursome is English, Flavourful is American. One is fine if you want to be follow a British English tradition. The other is fine if you want to follow and "English" tradition. You choose. I prefer flavoursome as it lack the more superlative "Full" that is common to US speak such as "Awesome", "Awesomer" or "Very Awesome". All of which make my teeth ache. Sorry that's just how I feel. The overuse of the superlative in US English makes people seem superficial, facile, disingenuous and phoney.
Why shouldn't the Americans change parts of what was once a common language to suit "their" version? And in fact they have retained some words that have dropped out of usage in English English.
I agree entirely that American English can and will develop separately from British English, but it irks me beyond explanation when American English is then imported to the UK, replacing our own version of the language; and we, being the saps we are, swallow it hook, line and sinker. It's American cultural imperialism (as Verbivore would call it), and we appear to be too weak-minded to resist it.
I too am irked by terms and constructions that are American, rather than English* English. But I wonder ... why? I can (usually) understand what's being said, and the American version is usually no less logical than the one I'm familiar with. The irking is, I suspect, something socio-biological, which works to protect our "tribe".
I'm not irked, I notice, when someone who does not speak English as the mother tongue changes the construction. It sounds odd - not "my" form of English - but it doesn't annoy. Again, why?
* It seems unfair to assume that Wales, Scotland and Ireland must speak the same form of English (or indeed English at all ...).