This is a genuinely clever question that deserves a better answer than a nested IF formula. What /u/sowtime444 is asking for, find tasks I've done elsewhere but haven't done at this specific location, is exactly the kind of relational logic that spreadsheets were never built to handle. Yet millions of users try to force it every day, stacking filters and helper columns until the sheet becomes a maintenance nightmare.
The problem isn't the user. It's that traditional spreadsheets treat every column as an isolated silo. You can filter column A, then column I, then manually cross-reference column B against another filtered subset, but the tool offers no native way to say "give me the rows where this value exists in one group and not in another." That's not a data problem. That's a language problem. The spreadsheet doesn't speak in relationships, so the user has to translate their intent into a series of mechanical steps that are easy to get wrong and hard to audit.
What makes this request so instructive is its practicality. This isn't a theoretical edge case. It's a daily workflow for anyone managing tasks, inventory, project assignments, or scheduling. The logic is simple: "Show me what I can do at P that I've already proven I can do somewhere else." That's a pattern that repeats across industries, field service, logistics, event planning, research coordination. Every time someone asks it, they lose minutes or hours to manual cross-checking, or they give up and accept incomplete data.
Our view is that this kind of query should be one line of human language, not a stack of conditional filters. An AI-native spreadsheet can understand the relationship between the three conditions and return the subset directly. It doesn't need you to break your intent into steps. It sees the pattern: person, location, task, and the exclusion rule. That shifts the user's role from formula-writer to question-asker, which is where human judgment adds real value. The next time you find yourself building a multi-column filter chain, ask whether the tool is serving your thinking or just testing your patience.