Being so upset with the progress bar not going smoothly, but if we think about it, it is more irritating, when the real life queue in the bank has a customer, who decides just to not being able to progress from the counter and you are standing behind them somewhere in the queue. Voilá, that progress bar is also not smooth, but now it is actually an irritating problem :D - not like the computer that you can leave there, or switch to another task if it is not operating system installation :D.