I like to use spreadsheets with Zapier - collect data from Google Forms.

I created a form for questions I wanted to ask myself daily.

Each day's input gets collected into a google sheet for posterity.

My friend and I needed a way to integrate multiple API data sources with spreadsheets so we made a Google Sheets add-on using Google Apps Script and published it in the G Suite Marketplace.

Discovering field sales people having affairs!

This goes way back to the days of Lotus 1-2-3 (DOS version, 3D worksheets and all that good stuff)

I used it to cross reference fuel card reimbursements and expense reports and as well as uncovering the usual expected low-grade expenses manipulation uncovered a couple of sales people both claiming for the same hotel room. That was an awkward conversation :)

More recently I've used Excel as a relational database because we weren't allowed to use Access. Huge amount of work involved, clunky as anything, and prone to errors but worked around the restriction and delivered massive results. It's the sort of thing you'd just do in Airtable these days.

Here are a few of mine:

• Creating Markdown-formatted linked lists. Say I wanted to make a list of apps and link to their Capiche profiles. I'd make a spreadsheet with the names in one column, the links in a second, then add an =concatenate formula that would first add a - [ to the beginning, then add the name from the first column followed by ](, then the link followed by ). Copy the formula to each row, then copy out the generated text. You can even generate the URLs if they're the same as the product names, which would be the case for Capiche links: Instead of adding the URL column, I'd add https://capiche.com/ followed by =lower(A1) or whatever the product name column is to generate the URL. You can use the same trick to create HTML lists or anything else repetitive—it's more tedious with HTML, but still faster than writing everything out yourself.
• Sorting and formatting any lists. Got a text list of names, say, you want in alphabetical order? Add it to a spreadsheet and sort the column, then copy back out. Similarly you can use spreadsheet formulas such as =lower to format the text in a list of stuff.
• Remove duplicates from a list. Paste a list into Google Sheets, then select that column and click Data -> Remove duplicates.

I've used spreadsheets to build a model for our business and forecast how we will do given the current numbers and course correct sooner rather than later. Helped me and my team focus and hit our targets each time.

You can use Google sheets combined with prediction API here https://developers.google.com/apps-script/advanced/prediction and use sheets to read data and predict support case outcomes like CSAT / DSAT, how long a case may take based on the description etc.

Having a passion for finance, I do a lot of finance stuff in spreadsheets:

• I track my option trades in Google Sheets. It helps me see certain numbers at a glance without having to build a complex database for it.
• I use spreadsheets to track my credit card hacks. It's good to see when 0% interest runs out on each card.
• Run cap rates on real estate investments. No other way to do this except on a spreadsheet.
• Calculate business acquisition valuations - input a few numbers, and spit out some great valuations :)

I recently started playing around with Google App Scripts and created some custom formulas based on the Goodreads API, like automatically fetching the author of a book using a simple formula like =GETAUTHOR(A1). I loved the process of creating it, I wish there was an easy interface to do that though.

I wrote about the process here:

• Full disclosure that Airboxr is my product (but I'm not the technical person in the team, so the real product is a lot better than my instructions here).

We have a feedback poll on Google Forms which is sent regularly to eligible users on Intercom. The responses then fall into spreadsheets raw data sheet and feed the dashboard (again on spreadsheets) to generate some graphs.

I’ve been using Sheets with Glide to make quick data collection tools. I recently used that combo to create a light CRM for an event. It’s a great combo for lightweight data entry.