[dasmoth]

There's some truth in this.

The best solution to this is that if you've got something non-urgent that you'd like a colleague to think about at some point, use a truly asynchronous medium (e.g. e-mail, so long as you're not in an organisation which uses it as a de facto IM platform).

This is true whether or not the people you're trying to communicate with are in the same building.