There's more to it than "passion for programming/work" or losing the notion of time that passes. If you've teammates or clients who are a few timezones to the

There's more to it than "passion for programming/work" or losing the notion of time that passes. If you've teammates or clients who are a few timezones to the west of yours, then: 1. You only have so many things you can interact about in the couple of work hours you share with them (assuming any at all, when you're in Europe with Californian colleagues or clients), so it's occasionally tempting to work "just one more hour" to make sure a project moves forward. 2. You periodically get dragged into "this can't wait until tomorrow and you need to be here; no, seriously, you're needed and it can't wait until tomorrow!" types of discussions to sort out emergencies.