Yes, we English do have an annoying habit of using 'weasel words' and 'not calling a spade a spade', although people in northern England tend to be more blunt (ie, they say what they mean and mean what they say), and in Scotland (especially around Glasgow) they're even blunter. So if you tell your boss that you'd like to work fewer hours because working full-time is tiring you out, you're likely to get the following replies:

* In southern/south-east England: "Thank you for telling me that, I'll think about it".
* In northern England: "I can't allow that, I'm afraid".
* In Glasgow: "F*ck off".

They all mean the same, of course....

This was demonstrated very well in the 1980s BBC comedy series 'Yes, Minister', which ridiculed both groups. Here a government minister is being asked by his senior civil servant to routinely approve the awarding of honours (special titles such as Order of the Garter, OBE, Sir etc) to a list of civil servants working under him, as part of the annual Honours Awards. When the minister says that he'll only give them awards if they can show that they've made economies, the senior civil servant tries to delay the minister's plan:

http://m.youtube.com/watch?v=qmXzGI0XP7M

Если что, это о писателе и его книге. А, как это?

why avoid? - just use some caution and common sense.
well, unless you want to talk like people in textbooks do (i.e., in schoolmaster's English), which is rather boring.

here is an example taken, or rather mercilessly ripped, from "Black Adder the Third: Dish and Dishonesty (1987)"

(William Pitt the Younger (who looks like a 15 year old boy) appears and is confronted by Prince George and Blackadder)

Prince George: I say, Blackadder, are you sure this is the PM? Seems more like an oily tick to me. When I was at school, we used to line up four or five of his sort, make 'em bend over, and use 'em as a toast rack.
Pitt the Younger: It doesn't surprise me, sir, I know your sort. Once, it was I who stood in the big, cold schoolroom, a hot crumpet burning my cheeks with shame. Since that day, I have been busy every hour God sent, working to become Prime Minister and fight sloth and privilege wherever I found it.
Blackadder: [Casually] I trust you weren't too busy to remove the crumpet.

British private schools have always had a reputation, deserved or not, for homosexual behaviour between their pupils, particularly sexual abuse of the younger pupils by older ones. This is probably because, in the past at least, many of the schools were single-sex only, so their pupils didn't see members of the opposite sex. Hence the reference in the Blackadder clip to lines of boys bending over as though they were on a toast rack.

Ironically the private schools were previously called 'public' schools, but now call themselves 'independent' schools, ie independent of the state. In the UK, a person who has had an expensive education in an independent school, but nevertheless turns out to be stupid as an adult, is referred to as a 'public school twit'. It's thought that this expression is one reason why 'public' schools decided to re-name themselves 'independent' schools.

http://www.harrowschool.org.uk/index.aspx