Having got a motorbike myself...
...I'd say that really it's a bit of both. Seen some terrible biking on the roads, and don't understand why they feel the need to do it. Filtering down the lanes between stationary traffic is ok, but weaving in and out of moving traffic is just stupid.

There's a biker who visits someone on my road who cranks it up on his way out - an R6 hitting the limit in first gear is travelling considering it's a 30 zone. Hope the karma he deserves heads his way.
(BombayMick Dogs are better than cats, Wed 13 May 2009, 9:36, archived)