When Scheduling Meetings Across Time Zones

This is a big deal to me.

It's just good customer service.

When you have a client that is in Time Zone A and you are in Time Zone B, then you need to talk about meeting times and project times relative to Time Zone A.  

In other words, don't be a jackass and make your customer do math in their heads.  Most of the time, they will do the math wrong, anyway, and your meeting time will be screwed up.

Likewise, if you have clients in multiple time zones, you need to use the time zone of the headquarters.  So, if the headquarters is in San Francisco, for example, you need to refer to all project times according to Pacific Time.  Your client will be used to having to do the math relative to their headquarters. 

It's amazing what a difference it makes to your customers.