Hopefully you're on a multi lane motorway when doing that. There are no motorways in my county, only dual carriageways. This means that when a car sits at 55mph in the left lane, and forces a HGV to overtake them at 58mph in the overtaking lane, it slows everyone to sub 60mph causing massive brake ripples and huge tailbacks. Unsurprisingly, there are accidents on these roads every single day. Very few of those are caused by excess speed!
It still baffles me as to whether people don't understand the ramifications of their actions, or whether they just don't care.
As I say, this is specifically for dual carriageways. Multi lane motorways are more capable of managing slow traffic in one or two lanes.