I have, in the past 3 months, been forced to work in a location where the only internet access is on machines with IE8 on them (and no ability to install Chrome Frame). The loss of Trello has absolutely FUCKING sucked. I'm sorry for the profanity, but it is an abysmally awful process to have to STOP using Trello and go back to emailing spreadsheets back and forth or shudder MS Project.
I think this huge drop in my productivity is a testament to just how awesome Trello is.