Accounts and the EVM

Ethereum has one address format, but not one kind of account. The network separates human-controlled entry points from code-controlled destinations, and that distinction explains most wallet and contract behavior.

This model makes contracts powerful but predictable. A Uniswap pool cannot wake itself up; it needs a transaction or internal call, and then every node runs the same bytecode with the same calldata and gas budget.

It also frames account abstraction discussions. Much of Ethereum UX work is about making user accounts behave more like programmable contracts without breaking the security guarantees users expect from simple key ownership.