Occasional ums and ahs are fine but when every other phrase starts with a long aaaaah it can be pretty unpleasant to listen to.
Looking at it again he'd pause, probably trying to find the next word, doesn't find it, and goes "aaaah". So watching at >100% speed and with skip silences saved my sanity: https://www.youtube.com/watch?v=dCO633KE7RA