I think the most offensive thing is seeing that the connecting flight left early (and arrived early). I missed SFO-HKG once because EWR-SFO was very delayed. I even bought WIFI, got on twitter and got them to contact operations to request that the flight waits. About 10min prior the landing, I was notified that they rejected my request. I could have made it to the gate prior to the departure time, instead, the flight left over 10min early and arrived close to 30min early. On another occasion, long ago, I scanned my web-printed BP, was part way down the jetway when I was told I need to go back to security. They reprinted a new BP with SSSS (which wasn't on my web BP) and told me I had to go back to security for extra screening and I should run because they won't wait. As I was running back (to the last gate in the terminal), the GA saw me and motioned to me to hurry up. When I got to the door, they told me I just made it as they were closing the door. Once onboard, we were delayed 30min because of a broken toilet.