On my regular commute I never filter on the left and thankfully there are no cycle lanes that encourage it, I don't see many other cyclists on the main road part of my journey. I do occasionally get people wandering over to the centre white line in the usual walking-pace queue that I regularly encounter, I can see their heads bob to the mirror then the car drifts across, but the traffic coming the other way (away from town) is so light that its never a problem. I don't really understand what they are trying to achieve as they will slow me down for all of 5 seconds then I'll be on my way again.
One phenomenon I've seen is people overtaking as we are approaching the tail end of a queue, then pulling in extreme left against the kerb to cement their position in front of me so I can't re-pass, these drivers all make the mistake of assuming I'm going to try and filter between them and the kerb like some sort of imbecile. My strong road position (looking to filter on the right) very rarely causes slight consternation as people try and get in front but 99% of other road users on my commute are pretty good and realise that we are coming up on the tail end of a queue and that a cyclist will make easy progress (same time/place every day). The 1% who cause a bit of bother must think that I'm "cheating" or something, not queuing with everyone else or some other such nonsense. Don't hate the player, hate the game!
I've been actively blocked a few times on my motorbike when filtering - people in L2 of a dual carriageway moving left to sit over the white line, but few people appreciate how fast even a modestly powered motorbike can do 30-60 and just simply go round the other side

. Sometimes I wave thanks - as if they moved left to allow me to pass on their right, rather than them blocking the filtering gap in between - but by the time my brilliant wit has soaked through their thick skulls I'm already reached home in time for tea and medals and they are still in traffic

