I've just been on an online training course and honestly the person delivering the talk said "you know" every other sentence. I actually had to quit because I had such rage.
The presenter has done many online videos that I've found very useful but this is the first time I've heard her live.
I appreciate that live presenting is difficult (it's a huge part of my job), but if you have such an obvious linguistic tic, PLEASE do not inflict it on your listeners.
I need to calm down I know, it is beyond a first world problem, but my ears are hurting from the "you knows". No, I don't know! That's why I'm attending the training.