Networking :: Browser "waiting For ..." Stalling / Browser Seems To Stall For A Long Time?

I'm surfing along just fine when I select some link in my browser.The status line reports "... waiting for ..." and the browser seems to stall for a long time (minutes). Often, but not every time, I can select the STOP toolbar icon and reload the page. This time things work normally.

I have a similar but different malfunction running Evolution email connected to my hosted IMAP server. I select a message and see "... formatting ..." and then Evolution seems to stall for a long time (minutes). Rarely the stop-reload actions help reading email. Instead,all Evolution windows go dark grey and the entire desktop stalls.[Analysis -- It has the feel of a "network" issue provoking issues within Evolution itself rather than an Evolution-only malfunction.]

Watching the running system with 'htop' and similar, I do not see where some other application or service is sucking all of the available CPU time or such. [Analysis -- It has the feel that either the browser message or the email message were sent into limbo without reaching their intended destination. Stop-reload sends the bits to the right places and so I get results.]