This is one of those things where it took me a long, long time to figure out exactly what the symptoms of the problem was partly because it seems so strange and hard to believe. I'm sure a lot of people reading this will find it slightly incredulous, and all I can say is that for weeks before posting here I have been experimenting to confirm that this is in fact a problem as I describe.
The issue is that Google services, such as Gmail, search, Calendar, you name it, are all significantly slower than any other web site when I am using WiFi hotspots.
I have tested to be sure that this is the case across multiple WiFi hotspot services providers, across at least a dozen different physical locations spread throughout my city. I have also tested to make sure that this is just Google with the issue, and not other web sites. Of course, I can't test every other web site on the internet, but I think I can reasonably claim that a huge variety of web sites from various countries, various companies, and via various services all come in at snappy speeds. For example, as I'm writing this now, Google is taking forever to load a search, while here on Stack Exchange I'm going through pages and filling out this question form as if the servers were next door.
One suggestion might be that it could be my laptop (running Ubuntu 12.10) that has some configuration issue that interacts with Google slowly. But, when I take my laptop home and use my wifi connection there, Google services are as quick and snappy as my desktop computer which has a wired optical connection (or at least it feels that way to me). Also, I have taken my laptop to friend's houses, and it works snappily there.
The key factors are that if I am on some sort of public or paid wifi hotspot service, all Google services, and only Google services, are frustratingly slow. Sometimes even failing to load.
How could this possibly be? What would differentiate how Google works over a wifi hotspot from any other web site or service?
And, most importantly, can anything be done to get Google services to be at the same speed as other web sites. I use Google a lot, especially Gmail, so this is quite an inconvenience.