Hey there! As someone who's made that exact transition from relay logic to PLC programming, I totally get why this can be tricky. The most counter-intuitive concepts that trip up experienced electricians are:

1. The PLC scan cycle - This is probably the biggest mind-bender. In relay logic, everything happens simultaneously when power flows. But in PLCs, there's a sequential scan cycle: read inputs, execute program, update outputs. This means your ladder logic gets evaluated from top to bottom, left to right, which can create timing issues you wouldn't see in hardwired circuits.

2. Virtual vs physical wiring - You're working with software representations, not actual wires. A single input can be used in multiple places without needing physical connections, which feels weird when you're used to tracing actual wires.

3. Memory and state retention - PLCs remember states between scans, while relay circuits reset when power drops. This means your ladder logic can have "memory" that traditional relays don't.

4. Instruction order matters - In relay logic, parallel paths work independently. In ladder logic, the order of rungs affects how signals propagate through the scan cycle.

To bridge this mental gap effectively:

• Start by drawing your relay circuits first, then translate them directly to ladder logic - this builds confidence

• Use simulation software to visualize the scan cycle - seeing it step-by-step helps internalize the sequential nature

• Think in terms of "software relays" - each contact and coil is a memory location, not a physical device

• Practice with simple circuits first - master basic AND/OR logic before moving to timers, counters, and more complex functions

The key is to leverage your existing electrical knowledge while gradually adapting to the digital, sequential nature of PLCs. It's like learning to drive an automatic after years of manual - similar concepts, different execution!