In the 2000s, my bank was acquired by some bigger bank from another country. Their long standing, well working and fast banking application was replaced with a very dysfunctional Java applet thing. I was using Linux at the time and IIRC it either worked barely, or then not at all. I phoned the bank, and they told about a secret alternate 'mobile' url, that had a proper working service. I used that for a while before ultimately switching to another bank. The bank sent apology letters to customers and waived some fees also as they saw many of them leave. It made me really wake up that to the fact if the company can do these visible level blunders, what else is going on there, and also, how the customer is in such a vulnerable position.

On the other hand, NASA in the past had some really great Java applets to play with some technical concept and get updated diagrams, animations and graphs etc.