Though occasionally it is necessary when turning in or out of narrow roads. In fact, turning left out of a T-junction near home, I always hug (but don't cross) the centre line at the junction. It's the only way to avoid either crossing the centre line of the road I am turning into, or mounting the kerb while cornering - it's quite a tight turn. That said, that is an exception and not the rule.
On a similar note, another annoying thing. Car turning right from side turn into busy main road with filter lane and lots of hashing in the middle of the main road. Because of the traffic, it's often necessary to "force" your way out, or wait till someone approaching from the right (i.e. nearer side of main road) to let you out, then wait for some kind soul coming the other way to slow and let you out the rest of the way. Now, most people will pull into the hashed area and go parallel to the traffic while waiting for the second person to let them all the way through, so letting the first crossed lane to proceed (are you following this :-). But others will just sit right across the road, thus continuing to block the person who let them half way in the first place, quite unnecessarily. I know all this is not "standard" driving, and wouldn't pbutt any driving test, but going by the book would leave you waiting at the T-junction till the end of rush hour. Such people need to drive a bit in the US, where 2-way turn center (sic) lanes are quite common, and that is a much-use way to turn in and out of left side turns (you do have to watch for people about to pull into the bit of center lane you're about to use).
