As far as their telling us, the failure didn't cascade causing their queues to fill up and other horrible things to happen. As far as we know, no mail got bounced, no mail got dropped on the floor and lost permanently, etc.
A 2.6 second delay isn't even worth mentioning, how could one even tell the difference between a 2.6 second delay due to a problem on google's side, or routine problems in the email network outside of google that could easily lead to a second delay or whatever.
Did people really get upset about this? Was it worse than it seems because of details they are ommitting? Are they preemptively advertising how well they dealt with this barely-a-problem-noticeable-to-users problem, because the message is really "see, look how damn stable gmail is, our worst problem ever is barely noticeable"?
Or, what?
Maybe those 1.5% of messages were all to the same users, so some people had no delay, and some people had ALL their mail delayed a couple hours? That would make it more noticeable.
But in general, occasional (like once a year or less) couple-hour mail queue delays should probably be expected from any mail provider, no?