I'm guilty of jumping between pavement and road. However, I do this depending on the particular stretch of road and pavement and more importantly as a reaction to the drivers around me. If I fear a driver is going to do something stupid and bring harm to me (as people just love to hate on cyclists), I try and jump onto the pavement for a little bit. Likewise, on the pavement I can't always go thundering down due to pedestrians and thus I'll hop off onto the road to avoid harassing them.
Earlier, I was riding in the road and had a car sat behind me for quite some time. The road began to narrow to a red-light and I was unable to / unwilling to filter down the left side of the cars to the front. As the car behind me got too close for comfort, the fact the road narrowed ahead and the fact it was going up hill and I was likely to get bullied into a lamp-post, I quickly sped up and hopped up a curb ready to cross a pelican crossing instead. At the back of my mind, I was already thinking about plebs like the OP complaining about it.
I'm always courteous of others around me which is why you will find me hopping between road and pavement. I'm perfectly happy to stick to the road, but conditions are not always as safe for me sitting on a light frame as it is for drivers inside their little cages. As a cyclist, for your own safety more than anything, you need to be a little pragmatic.
Let's take the other night for example, shall we? I was riding home from work in the road, lights blinking on and off, coming down hill. I'd just crossed one mini-roundabout, then as I came to approach another, a taxi which was sat there for a little while decided to pull out on me then slam on his brakes. I'd anticipated what he was going to do, so I was ready to respond and whilst riding my brakes, I just glided around him and gave him a little wave to let him know it's not a big deal.
Now, my question is this: I could've if circumstances had transpired differently, ended up in hospital thanks to this situation. What would you have me do in future? Continue to risk such an injury from drivers not paying attention, or being aggressive, or simply hop on the pavement when approaching such junctions and avoid it altogether? Incidently, I also nearly had a woman on a school-run nearly run me over as she wasn't paying attention a week ago too. All this because I decided to ride in the road for a change.
If you've got nothing better to do than moan at a cyclist simply pragmatically navigating their way from A to B whilst causing no harm, being considerate, but doing nothing more than alternating tarmac, then I suggest you grow up.
Don't forget cyclists can also become tired, unlike that 1.4 combustion engine you're relying on. It makes sense to hop onto the pavement from time-to-time, lest the cyclist hold up any more impatient cretins behind a wheel of a car.
If you want to rage at something. Rage at the fact that an adequate cycle infrastructure doesn't exist in this country and instead cyclists are stuck between a rock and a hard-place; ride in the road and you **** off drivers. Ride on the pavement and you **** off everyone else. Or, why not rage against all those stupid women who still think it's appropriate to drive whilst on their mobile-phones and in charge of a few ton of potentially lethal machinery.
The only thing that I will never condone is cutting a red-light; that's just complete stupidity.