Quickbooks and to a lesser degree Windows.
This is around 2000 or so: Quickbooks was keeping customer data, requiring you to keep their service forever. They also got in trouble later on for selling customer data. I noticed that Quickbooks did nothing but make an accountants job easier, so why didnt the accountant pay for it?
In any case, the biggest issue was I hated quickbooks (Intuit) as a company, AND they required a license for each machine it was installed on, requiring either additional licenses or getting people to enter data on the same machine.
I ran a small business that visited clients in many nations, so I learned Linux, built out an accounting tool myself, and then served it as a web page and an X forwarded app to clients anywhere in the field. I started hosting my own website, running my own email, and it just grew from there.
TL;DR: Intuit can suck it. Vendor lock in and vendor rules make me choose to make my own rules.
This was quite a long time ago (2000-2005), it was really simplistic by todays standards but tailored to my needs. All of that is long gone now, it is just what kicked off my interest in hosting my own stuff.