Well, I find that people do say "thanks" when you give way, so maybe it is you (or where you live)?! Only joking - you've just witnessed a bunch of drivers with no manners (on or off road I expect).
As for not paying atention - hell yes! So many drivers these days seem to think they are in some entertainment centre, rather than a 1 tonne+ potentially lethal moving object. The number I see texting, or on mobiles, or faffing with their Garmin Tom........unbelievable. And as for women fiddling with their hair or actually applying make up whilst driving - it's the only time they use their rear view mirror!
Only yesterday - M27, lane 3, woman driver in ML Merc, car full of kids who appeared not to be wearing seat belts, totally unaware of the ambulance behind her with full siren and lights going.
And don't even start me on elderly drivers wearing hats, usually behind the wheel of a Honda Jazz or Rover 75..............