I got a bunch of software certs for when I was first job hunting and now they either no longer exist or have been so changed that the certs don't matter.

As an old time computer nerd I have uncountable examples of deprecated knowledge. There is no use in knowing how to use the reserved upper memory in autoexec.bat and config.sys, nor how to use Napster or Kazaa.

But all these skills do shape your brain and way of thinking.

Assembly language taught me to be precise and think before typing. Flash taught me that nothing lasts forever, as big as it might seem.

Eventually, all this adds up and creates a profile that is very demanded in my career.

That said, my mom taught me to thread a needle without looking. And I can't sew, so that's that.

I'm a trained electrician. Despite taking and passing a reputable school for it, I can't get licensed to do it in my state because you have to have 2 years apprenticeship. You get an apprenticeship you have to go through a school supported by the union. The only school supported is the one they own.

Despite being fully capable of wiring a building to code, installing a solar array or electric car chargers I can't do shit with the information and it way a year and $2k fucking wasted.

English sheep counting, a base-20 number system. Often called Yan Tan Tethera. Lincolnshire is the best version.

Can't think of anything.

Life's a journey, not a destination.

Probably morse code. It was required for my ham radio license back in the day to read it at 10 WPM. I put quite a few hours into learning it through the koch method.

At the end of the day I'm just not very interested in getting a lot of contacts. I just like building and tinkering with radios.

Getting a private pilot certificate. Was fun, but after going to every airport within range, not sure it was worth it.

I got my Realtor's license without realizing just how much it cost to break into the business. I did it for a year, and then dropped it.

That's the only one I can think of. Typically, I don't learn on spec, I learn as I go, "on the job". So, what I'm learning is directly applicable to what I need to do.

For instance, I recently refurbished an old, cheap desk. I learned to apply laminate with contact cement. It's not hard, but it was my first time doing it. A few weeks later I'm at a counter at a business and they have laminate that is separating from the base, and I knew exactly why. They told me that someone had been hired just a few weeks earlier to repair the same problem, and it happened again. I knew how to fix it right, but I didn't need a job so I just commiserated with them.

I ruined my diaphragm learning how to burp my ABCs

It was only sort of worth it

Making tofu from scratch. Also sourdough.

I love cooking in all forms, and there are a lot of things I happily do from scratch. I love baking bread, making my own oat milk, mixing up my own seitan from vital wheat gluten, and a whole bunch of other things.

But making tofu was something I tried a bunch of times and have ultimately given up on. It is extremely time consuming, very difficult to get right, and makes a worse product than what I can buy at the store. It isn't even cheaper to do, as the cost of the soybeans and the cost of the premade tofu are about the same. I may make it on occasion if I plan on serving it on its own as a dish with soy sauce, but that is about it.

With sourdough, I found it easy to get into, but my husband and I both prefer our baked goods to be not sour, and we both have pretty sensitive tastebuds in that regard. It is easier for me to just use instant yeast whenever I need it and make something we both prefer to eat.

People pleasing, spent nearly four decades getting so good at it thinking if only I could be just that little bit “more good” that I’d get what I want and need from people and relationships only to realize I’ve been plenty good this whole time, it’s a fools errand and I only attract people who will move the goal posts every time because it’s what I expect and have trained for

I learned how to work hard and be good at my job and actually get things done, not just look busy and act important.

Jokes on me, the entire management make 100x more than me and do 100x less. And they get to spend hundreds of millions on stupid projects that are horrible ideas, but I have to cut back on my area to save $100.

I should have put all my stat points into soulless bullshit corporate jargon and none into intelligence.

I learned one of the major orchestration tools (puppet), dabbled in the second (chef), and got a third running everything in my home lab (ansible). I refused to learn the 4th (salt). I figured my time was better spent learning python.

Cursive I guess.

Even if you don't end up using it, the process of learning something often shapes us into who we are. So it's tough to say something isn't worth the effort.

For example, I learned to read sheet music when I was younger and taking piano lessons. It took a while and I don't really use that skill today since I mostly play by ear or tab (fretted instruments). However, I appreciate understanding what the notes mean and think it made me more musical overall.

I can't learn skills I don't like to learn. As time wasted having fun is time well spent, I never learned a skill not worth the effort of learning it.

I got half of my A+ certification before deciding fuck this and going into a different career. I can code very simply, I have very basic networking skills, and I use none of it. I'm amazed at people who can do it but I am not cut out for IT anything I don't think. Too much work.

I honestly can't think of any, even though I have many examples that objectively seem to not have been worth the effort.

Easiest example is flight school. I went to a tech college for its professional piloting program. Got my private pilot cert and multi engine rating, and completed IFR in the simulator. But when it came time to sign up for IFR in a real plane, I couldn't get approved for enough student loans to cover the cost, so I dropped out, switched to business school, got a tech job, and dropped out of business school too.

By all accounts, the debt I racked up (like $75k) and the pilot license I haven't exercised in 14 years are all a huge waste. And my flight instructor was such an impatient ass that I feel mildly scarred from the times he yelled at me.

But, I will never get over the massive feeling of accomplishment I got from earning my private pilot certification. And even more so, earning my multi-engine rating. Even if I failed a part of each of those checkrides and had to retake those portions, I passed them. Even if I never fly again, I am so fucking proud of myself for earning those.

I guess since I never actually graduated from any of the many colleges I've dropped out from (three or four depending on how you count), pilot license is my closest analog.

Also have a CDL and skill with docking 53 foot trailers, and tons of forklift experience. Those haven't been used in a very long time and I may never use them again, but still feel like important parts of me.

Driving. Never used it.

All the useless mathematical technics from studying physics at university. Now working in software engineering, I barely use more than highschool math, sometimes.
Instead of spending weeks writing down equations I wish I had learned more about science history, breakthrough experiments, other sciences etc.
Those maths are only useful for a tiny percentage of the students that will eventually become theoritical physics researchers.
It's the curse of studying science in France, it's unnecessarily math heavy.