There's a lot of caching in this site, mostly the lazy loading type. There's always opportunites to revisit this to optimize the caching.
You can set up an automated test of hitting the site from a test program and then chart it's response time.
You may be shocked to see that it gets faster the more often you hit it, up to some point, and then it starts slowing down again. This is a characteristic of sites that do a lot of caching. This is especially true with a third-party hosted site. If you set up an automated program to hit your site about once every 10 seconds, the overall response time for other users may improve. This will keep your app domain active and keep the caches full.
And there's another factor that the hosting companies don't want you to know about. The more active sites often get migrated to servers that have fewer sites on them. This gives you higher performance for no additional charge - provided you don't go over your bandwidth limit (if you use a hosting company that has a limit for your plan).
How do you know how many sites are active on the server your hosting company assigned you to? Check www.whois.sc
and look at the reverse IP info.