And then not indicating left to leave the roundabout. In fact any failure to indicate correctly at roundabouts gets my goat, there's no excuse for not giving the correct indication at the correct times - all roundabout users are sat there and shouldn't be doing anything else other than negotiating the roundabout and indicating correctly.
While on road habits that get my goat there's these:
- coming to halt in a traffic queue then randomly creeping forward some time later before the queue has started moving. What's that all about anyway?
- creating a second lane when one is not marked, particularly approaching a roundabout
- sitting on the brakes in a traffic queue, dazzling drivers behind, particularly modern Mercedes that have very bright brake lights
- indicating right to pass parked vehicles - oh really you're going to pull out? I thought you'd plough into the back of that parked car... (similarly indicating right to join a main road at the end of a slip road - wasted information, nobody ever ploughs into the nearside verge instead of joining the main road.)
- using hazard lights when (badly) parked, particularly when the nearside lights are obscured
- slowing to 18mph and creeping around the outside edge of a clear roundabout. For crissakes, have you not seen and dealt with a roundabout before? Just straightline it and clear it....
- not merging in turn when two lanes become one, instead accelerating and closing the gap to make life difficult, slowing everyone behind
and finally the worst that's pretty much endemic in the UK:
- slowing and holding up a line of traffic behind to let in a vehicle, often slowing 20 cars (with all the ensuing brake dust emissions etc.) to enable one vehicle - that was waiting quite happily - to join a traffic flow. Extremely bad practice.
All these are covered by the Highway code but nobody seems to take a blind bit of notice.