Some drivers seem to think cyclists hold them up.
Some drivers appear to maintain whatever illegal speed they are obliviously trundling along at, regardless that they also have to safely pass a cyclist somehow, within a tight & hazardous urban landscape.
It is then, by logic and self-preservation, that cyclists arrive at the conclusion the whole lane must be necessarily taken, to deny opportunity for such careless overtakes, trundling, and skimming.
So yes, the drivers have lost time, probably about 5 seconds or something. And the sensation of dropping to 2nd gear, reducing by 10 or 20mph I guess is where some "loss" is felt. But the occasional drivers' narcissistic misconception of their own importance, compounds this event, because they are forced to decelerate their status-symbol vehicle, but also decelerate their Mc-lifestyle ambitions of "life in the fast lane".
Well here's some news; what was the fast lane, is now backed up with traffic for the next 2 miles. Get with it! Traffic as congested as it is now, plus the proliferation & extent of traffic lights, it really is quite acceptable to pootle behind a cyclist and take it easy:- Because you KNOW what is 'round the corner...
For answer to the picture question, and an excellent demonstration of the cause & reason, this link is mandatory viewing! - Here: ChapmanCentral.co.uk.