I've never played a bullet game in my life; and being extremely new to chess (4 months now) I thought I'd try a 1+2 Blitz instead. After several no starters and horrible blunders from moving too quickly; I got a game that was reasonably OK for me. I have a new respect for the speed of calculations people pull off ..
When I took a look at the ultrabullet games played by 'toivok', who is rated about 2600 in this time control and is currently number one on the site, I noticed that he had been practising with the 1350-rated engine. He had a lot of losses and only a few wins to the engine at this strength, which I found surprising until I realised that flagging is simply not possible. You have to find checkmate every game. Having tried to win against the AI myself under these conditions I have newfound respect for people who can play ultrabullet at a very high level.