When the user's client-side timezone settings differ from the user's server-side timezone settings, we should prompt them to reconcile the discrepancy. The option in Settings is easy to miss, not very convenient when you travel, and client timezone settings are probably trustworthy most of the time for Phabricator users.
Original Description
The timestamps are all in Pacific time. It'd be better to convert them to the user's time (according to their browser's timezone report), but we should at least say "GMT-8" or "PST" or something in our timestamps.