Oh man, let me tell you about the most frustrating vendor lock-in I've dealt with! It was with a proprietary PLC (Programmable Logic Controller) system from a major industrial automation vendor. We had this entire manufacturing line running on their ecosystem - their hardware, their programming software, their HMI (Human-Machine Interface) panels, everything. The real kicker? Their programming environment only worked with their specific hardware, and the licensing costs were astronomical every time we needed to make even minor changes.

The worst part was when we tried to integrate a new piece of equipment from a different manufacturer. Their system used completely proprietary communication protocols that weren't compatible with anything else. We were stuck paying their premium prices for every expansion, and their support contracts were eating up our budget.

Here's what we did to work around it:

1. We created a middleware layer using open-source tools like Node-RED and Python scripts to act as a translation layer between the proprietary system and other equipment. This gave us a way to integrate new devices without being forced to buy everything from the same vendor.

2. We started implementing OPC UA (Open Platform Communications Unified Architecture) wherever possible. This standardized communication protocol became our bridge between different systems, reducing our dependency on proprietary protocols.

3. For new projects, we moved toward more open standards like IEC 61499 and started using containerized applications that could run on different hardware platforms. This gave us much more flexibility.

4. We also created detailed documentation and data extraction routines to ensure we could migrate our logic and configurations if we ever decided to switch platforms completely.

The key lesson? Always design with exit strategies in mind from day one. Don't let any single vendor own your entire automation stack!