The 10 Biggest Mistakes of My Career
A wise man told me if you want to build a good life, learn from your mistakes. If you want to build an amazing life, learn from someone else's mistakes.
I’ve been in the workforce now for just about 14 years, and there are many moments I’m still kicking myself for.
Today, I want to share them with you in the hopes that they will help you avoid the same path I went down.
The Mistakes That Cost Me Immediately
1. Sending Nearly 100 Tax Forms With the Wrong Social Security Numbers
What happened: A member of my team imported data into a spreadsheet without realizing it was offset by one row. Nearly 100 people received a tax form containing someone else’s Social Security number.
The lesson: You cannot review every detail, but you are responsible for building controls that catch high-risk mistakes before they reach a customer.
2. Sending Out a Board Deck With a $3 Million Error
What happened: A client had just raised a large round of capital and was preparing for its first board meeting. I spent weeks helping build a credible plan to present. The problem? A formula error caused $3 million of expenses to be excluded from the cash flow forecast.
The lesson: Every spreadsheet needs error checks. Whenever data moves from point A to point B, build a control confirming that it transferred completely and accurately.
3. Turning a Client Departure Into a Fight
What happened: Early in my journey as a business owner, I felt a knot in my stomach whenever a client announced they were leaving. It almost felt like they had let us down. During one departure, I got into a heated argument over the offboarding process and refused to cooperate unless the client paid more. In the process, I destroyed what had been a strong relationship for more than three years.
The lesson: A few extra dollars are rarely worth destroying a valuable relationship. Set reasonable boundaries, but make every effort to part on good terms, even when you believe the other side is being unfair.
The Mistakes that Took Me Years to Understand
4. Not Firing an Underperforming Employee Sooner
What happened: Early in my journey as a business owner, I hired someone who showed tremendous potential. Unfortunately, he was unreliable, and “Sorry, I forgot” became a frequent excuse. I kept giving him more chances because I cared about our people and believed in what he could become.
The lesson: An underperforming employee can become the biggest drain on everyone around them. Invest in your people, provide clear feedback, and give them a fair opportunity to improve. But when it becomes clear that someone is not working out, take action quickly.
5. Charging What We Could Instead of What We Should
What happened: When our firm moved from hourly billing to value-based pricing, we sometimes won contracts at higher prices simply because I believed the client was willing to pay. Eventually, some clients compared our pricing with competitors and felt they had been taken advantage of. When money became tight, many left for lower-priced alternatives.
The lesson: Profit matters, but pricing still needs to reflect the value you consistently provide. When the gap between price and perceived value becomes too large, it can damage your reputation and push even your best customers away.
6. Leaving the Follow-Up to the Client
What happened: After moving away from hourly billing, we felt less pressure to “babysit” clients for requested data. We sent the initial information requests but did not always follow up persistently. As a result, some clients paid for services they were not receiving. They eventually grew frustrated that the work was not getting done, even though we were waiting on them.
The lesson: If you need something from a client to do your job, obtaining it is part of the job. Follow up until you have what you need. With hourly billing, silence can stall the work and cost you revenue. With retainers, it can leave clients feeling cheated for paying for a service they never received.
7. Neglecting My Network
What happened: When I started my firm, I spoke with as many people as I could and formed some incredible partnerships. As the firm grew and my attention became fragmented, I stopped developing new relationships and investing in the ones I already had. Both my business and my quality of life suffered.
The lesson: Your network is one of your most powerful assets, and it takes years to build. Keep relationships warm, show up for people, and never stop connecting with like-minded individuals.
8. Wearing Too Many Hats
What happened: I have always prided myself on being a jack of all trades. That versatility helped me start an accounting firm, a media company, and a software company. What I failed to appreciate was the cost of dividing my attention among them.
The lesson: Meaningful success requires sustained focus. Doing many things can feel safer because you are diversifying your bets, but each additional commitment takes energy away from your ability to do one thing exceptionally well.
9. Optimizing My Calendar for Time Instead of Energy
What happened: I used to treat my calendar as an open schedule. Between 9:00 a.m. and 6:00 p.m., and sometimes later, people could book meetings anywhere, and I might work on almost anything. It took me years to recognize how much this fragmentation was reducing both my output and my energy.
The lesson: Energy comes in waves. There are periods when you can perform at your best and others when you need to recover. I now organize my calendar into 90-minute blocks, using each one for either deep work or three consecutive 30-minute meetings. I perform at a higher level and genuinely enjoy my days more.
10. Waiting Too Long to Enjoy Life
What happened: I spent years believing I needed to work until I achieved complete financial freedom. Only then, I thought, could I spend each day doing what I truly enjoyed.
The lesson: There is value in sacrificing today to create more freedom tomorrow, but you should not postpone your entire life in the process. Draw a box around the things you enjoy, protect time for them now, and continue working toward greater control over your future.
So what are the common themes?
→ Double-check your work, and build controls that prevent the same mistake from happening twice.
→ Prioritize relationships, recognizing that a strong network requires continuous investment.
→ Choose focus over fragmentation.
→ Don’t compromise your well-being for the promise of “someday.”
Revisiting these mistakes makes me cringe, but it also makes me grateful. At 37, I have already learned some crucial lessons that I hope to carry with me for the rest of my career.
I’m sure you have made a few mistakes I can learn from, too.
So tell me…what is one of the biggest mistakes you have made in your career, and what did it teach you?
Hit reply and let me know. I read every response.
Have a great weekend. And whatever mistakes you make, make sure they’re new ones 😜.
Josh (Your CFO Guy)
Thanks for reading my article. My goal is to help you grow in your career with proper Finance and Accounting.
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