I look enviously at the bikers filtering through traffic and think "Oh, how much quicker would the commute be on one of those"
Then I think of the smear I'd leave if someone changed lanes without looking, or how wet I'd get in the pouring rain, and I think maybe my cage isn't so bad after all..
Yup, then add in when it's 25c + you arrive in a ball of sweat because of all the gear on and low speed riding and pi$$ed off at cars pulling out and you and getting stuck while filtering. Then take off all the gear, stuff it in a locker and change into normal work clothes. To be honest, that combined with putting on the gear the other end nearly writes off all time saved on the journey.
Then when it's dark cold and -5 outside you don't want to take the bike, you want a nice warm comfy car that does not need 3 layers, thick gloves which you can't feel the controls or thin gloves with heated grips.
it's also another thing that needs MOT, tyres and insurance!