I like Pareto. I dislike what people do with it. A useful observation about how results are distributed has become a respectable way to say, "ignore most of the work." Find the small set of actions that matter, discard the rest, and move faster. Tempting.
There is one problem. You usually see the 20% after the result exists. The chart does not tell you which ideas will work before the team has tried them, made a few bad calls, and learned what the market will tolerate.
The winning ad had several bad ancestors
Look at a top-performing ad. It is easy to credit the hook, the offer, or the person who approved it. Harder to see the briefs that went nowhere, the edit that killed the joke, the audience test that contradicted everyone in the room, and the slow development of taste across dozens of attempts.
The result is concentrated. The learning was not. The same is true of judgment. A good operator may make three decisions that change the quarter, but those decisions rest on years of noticing what does not work.
The boring work is how you learn to recognise the useful 20% when it finally appears.
Use Pareto after the work has something to say
The rule earns its keep when a system has enough history. It can show where results cluster, where complexity has grown without payoff, or where a team is spending time out of habit. I have used it for exactly that.
Early on, the data lies by omission. A channel may look weak because the creative is bad. A retention idea may fail because onboarding is broken. Cut either one too quickly and the spreadsheet will congratulate you for saving money while the business learns nothing.
Some inefficiency is tuition
This is not an argument for keeping every task or funding every experiment forever. Waste is real. Remove it. But do not call all repetition waste. Some of it is the tuition you pay for context, and context is what makes later efficiency possible.
I find one question more useful than "What 80% can I skip?" Ask what the work is teaching you. If the answer is nothing, stop. If the answer is getting clearer each week, the boring part may be doing its job.