Jesus Christ. This is tough. How do you summarize the most important thing you did, in the most life-changing year of your life?

This is a letter to myself and my teammates, reflecting about my life in 2019 with regards to building Sail, an app where friends can build habits with each other. There are going to be two main sections.

One, product and YC lessons. Two, team and life lessons.

If you need more context, here was an update I wrote 5 months into building Sail, and here was a reflection about our YC interview experience.

Product & YC

Product and YC…

Today, I’ll be doing a product analysis of Masterclass. A beautiful product that is completely revolutionizing the relationship between celebrities and fans.

I’ll be walking you through the following…

  • Using the product
  • Analyzing the entire customer funnel
  • Discussing product strategy
  • Identifying pain points & opportunities for growth
  • And hypothesizing what the future of Masterclass looks like

A lot to cover—so let’s jump into it!

Product Overview

Masterclass is a luxury learning experience, where students are taught by the most recognized celebrities in each field.


Their target user is likely someone who is highly educated, is upper-middle class, and a young adult…

The $150,000 10-minute interview.

Was this before or after we pee-ed ourselves?

Aaron Epstein.

Tracy Young.

Kevin Lin.

Michael Siebel.

The names of our interviewers were scribbled down in black ink. Most of them I vaguely remembered reading somewhere, before. One of the names I had Google searched hundreds, if not thousands of times.

My head span. My hands were shaking.

I’m not sure if it was in awe, or in fear.

It was suffocating inside the nondescript office building. It blended right in with the rest of the quiet, suburban town of Mountain View. Inside, the pale, white walls stretched up to the towering ceiling. …

21 was a crazy year of life for me.


I got to do and try a million new things. More importantly, I finally started to form some opinions and principles around how I think I should live my life, and why.

Here are some of the things I learned :)

Sometimes you just get lucky

I had two job offers for this entire gap year — Jubilee Media and Datadog. I found out about Jubilee in January, and Datadog in February, after I had decided on the gap year. Two of some of the coolest companies to work for, in my opinion. Kind of insane.

I want to enable my friends, family, and of course, the rest of the world to achieve their dreams. To go beyond their fears and do things that they want. To pursue the projects and be given the opportunity to succeed. To have someone believe in them.

Why do I want to do this? Truthfully, it’s because I have seen firsthand how hard I had to work to accomplish a few awesome things in life. And so far, achieving certain dreams has felt, for lack of a better word, incredible.

But, I was also lucky enough to be raised in…


Saturday morning rolls around. Single, 24-year-old version of yourself is lying in bed. You look ahead at the two days out of the week that you don’t have responsibilities, obligations, or otherwise limitations on the way you spend your time.

Unfortunately, that also means that you have to figure out how to occupy your time for the next 48 hours. Hanging out with friends would be fun, but what would you even do? Grab a coffee, or go to a bar for the 100th time? Planning a whole trip somewhere would be a lot of effort. …


At my first paid internship, I asked the CEO what I could do to be in his position. Everyone in the room laughed.

You’re an intern, lol!

You should be making coffee and learning how to count!

Why don’t you worry about getting a return offer, first!

Recently, I decided to ask again — at Jubilee. Of course, I learned my lesson and didn’t bluntly ask about becoming a CEO. I asked if I could just sit in a few leadership meetings, instead.

This time I was laughed at by a million people.

But it was pretty cool.

I spent…

Why building habits is frustratingly difficult, and what you can do about it.

Ahh. Another sunny Saturday afternoon.

The 6 of us were sitting at a cafe together — all friends since before being able to read a book or lift a barbell. We were catching up on life after another long semester separated at college.

“Ugh, I’ve just been studying and drinking these past couple weeks. Honestly, I need to start gymming again.

“Same… I’m just so damn busy. Maybe next semester.”

“Yeah, me too.”

We all sighed.

And then proceeded to sit at the cafe for 6 hours…

HI! Thank you for opening this link! Sorry if David aggressively asked you to open this.

Long story short — we’re a group of three longtime high school friends (David Chang PM, Ryan Yue SWE, Young Guo SWE) building this “social habit building” app outside of our day jobs/school and we need a talented UIUX person to take our app to the next level. David tried, but he currently sucks at design.

If you’re reading this, we must think you are good and can save us from me.


At the end of the day, we are building this because we…



We as humans are constantly scared. We don’t think we can do things. We think we are dumb. We think goals are too hard to continue and maintain. It’s impossible to know for certain if we can or can’t; so why even try?


Instead, we assume things are the way we perceive them to be, because we have to assume. We have no data to back up any sound reasoning. We were too scared to try and find out for ourselves.

I am too dumb, but only because I’ve never tried to study.

Things are too hard, but only because

David A. Chang

I like products and I like people. Mostly. Building stuff at SprintRay.

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