A lazy note is the simplest form of writing. No structure, no formatting, no idea of doing it right.
You write down only what helps you not get lost, reminds you who you are and what you are doing, and helps you notice what is going on. There is no goal to understand everything or to make it pretty.
The biggest obstacle to writing is the expectation that it should be good. Take the expectation away and you suddenly write every day. The notes are messy, and they turn out to be the most honest record of what you were thinking.