Who ultimately executes contracts written in Solidity?
EVM execution must be deterministic: the same input must produce the same result on every node, otherwise nodes cannot reach consensus.
When interacting with different EVM-compatible chains, addresses may look the same, but you need to keep track of which chain your assets are on.
When calling a contract on Ethereum, the EVM charges Gas for every instruction it executes, paid using $ETH . Currently: 2066.23.
Have you run into any pitfalls like these? Share them to help others avoid the same mistakes.

For reference only. Use at your own risk.