This can be really useful… if your motivations are good.
Humans have a great rationalization system in our heads that works all the time, whether we want it to or not. For good or ill, we can rationalize away our motivations, past behaviors, and even trends. Our memories are faulty, emphasizing some things while ignoring others.
Taking notes and keeping a record can help correct for these biases in our observation. It seems like your spouse hasn’t been doing their share of the chores? Not enough kind words throughout the day? Keep track. They’re promising that they’re going to be better this time, honest? Keep track. See if the frequency of the behavior changes over time.
Heck, it also helps when you’re leaving a relationship. Looking back some things I wrote to myself about an abusive ex helped make sure that the rose-colored glasses stayed off my face.
This is important: If you’re using note-taking in this way, it must be as a neutral observational tool. The moment that these observations change from “Hey, honey, it looks like we need to work on this behavior” to “You did this thing that pisses me off five more times this week because you’re awful”, it’s a sign that note-taking isn’t a good strategy… and maybe a sign about the relationship itself.