Dear 25-year-old Felix,
You’re sitting at your desk in Graz right now, three years into an engineering career, certain about everything. The career trajectory is clear. The skills are developing. The salary is growing. The plan is working.
I’m writing from eighteen years in the future to tell you three things: you’re going to be wrong about almost everything you’re currently certain about, the wrongness will be the best thing that happens to you, and you should start being wrong much sooner than you will.
Learn to Sell. Now. Not in Fifteen Years.
You think selling is beneath you. You’re an engineer. You solve problems. Salespeople are the ones who make promises about your solutions. You’ll do the important work; they’ll do the talking.
This belief will cost you fifteen years. Fifteen years of being the smartest person in the room who can’t convince anyone to buy anything. Fifteen years of watching less technically skilled people build successful businesses because they understood that everyone is in sales and you didn’t.
You will eventually learn to sell, and when you do, you’ll realize it’s not manipulation. It’s communication. It’s the skill of explaining value in terms the other person understands and cares about. Every technical skill you have is worth approximately zero if you can’t sell the result of that skill to the person who needs it.
Start now. Take a sales course. Read a sales book. Offer to help the sales team at your company. The discomfort you feel at the idea of selling is the same discomfort you felt the first day of engineering school. You got over that. You’ll get over this. But start now, not at 40.
Start Building Something. Anything. Today.
You have a folder of ideas on your computer. Twenty-three product concepts. Eleven business ideas. Seven app sketches. All carefully documented. None of them started.
The cost of not starting is compounding daily. Every day you spend planning instead of building is a day of learning, revenue, and growth that you won’t get back. The product you launch today and fail with tomorrow will teach you more than the product you plan for six months and never launch.
Your first product will be terrible. You already know this, somewhere beneath the certainty. Ship it anyway. The market will teach you what you need to know, and the market is a faster, cheaper, more honest teacher than your planning documents.
You have permission to start small. A single product. A single customer. A single transaction that proves the concept. You don’t need a business plan, a website, a logo, or a brand strategy. You need a thing and a person willing to pay for it.
Your Body Is Not Invincible
You’re 25. You can sleep four hours and function. You can eat garbage and feel fine. You can skip exercise for months and not notice.
This won’t last. By 35, the sleep deficit will manifest as worse decisions, shorter temper, and diminished creativity. By 40, the exercise deficit will manifest as lower energy, slower recovery, and the three-week cold that costs you EUR 15,000 in business performance.
Build the habits now, while the habit-forming is easy and the consequences of not forming them are invisible. Sleep seven hours. Walk daily. Eat food that doesn’t come from a vending machine. These habits, formed at 25, will compound into a physical foundation that supports everything you build at 35 and 40.
The Relationships Matter More Than the Resume
You’re building a resume. Stop. Build a network instead.
The resume gets you hired. The network gets you opportunities that no resume can access — partnerships, collaborations, introductions, clients, mentors. The resume is a document. The network is an ecosystem.
Be useful to people. Not strategically. Genuinely. Help before you need help. Connect people who should know each other. Share knowledge without keeping score. The network you build through usefulness at 25 will produce more career value by 35 than any credential or achievement on your resume.
Find a mentor who will tell you the truth. Not a cheerleader. A truth-teller. Someone who has been where you’re going and who cares enough about your success to tell you when you’re wrong.
Things That Won’t Matter
The MBA you’re considering? You won’t get it, and you won’t need it. The specific company you work for right now? You’ll barely remember it in ten years. The technical certification you’re studying for? It’ll be obsolete in five years. The competitor you’re worried about? They don’t exist anymore.
Things That Will Matter
The five business failures you’re about to experience. Each one will teach you a framework you’ll use for the rest of your career. Welcome them. Learn from them. Document them.
The hotel room where you’ll pick up a deck of cards one late night. That moment will give you a creative discipline that balances your analytical training and makes you a better communicator, performer, and builder.
The woman you’ll meet who will ask you, years from now, whether you’re coming to bed while you stare at a dashboard that isn’t changing. She’s right. Close the laptop. She matters more than the dashboard.
The 40+ startups you’ll work with. The patterns you’ll observe. The frameworks you’ll build from those patterns. The books you’ll write that nobody asked for.
All of it starts with a single decision: stop planning and start building. The building will be messy, embarrassing, and unprofitable at first. It will also be the beginning of everything that matters.
You’re 25. You have time. But time is compounding, and the compound clock starts when you start — not when you’re ready.
Start.
Your 44-year-old self
