Long hours, little time for family. After a big push I'll be entirely strung out and exhausted, staring at a wall mumbling random thoughts like someone who suffers from dementia. It's miserable.
And rewarding in so many ways. My personal favorite is that at the end of the day I get to say 'Look at what I built! Millions of people are using it!'.. Nothing beats that feeling.
I'm not young anymore. I've done more startups than most. I'll eventually be taken as a joke no matter how up to date my skill-set is. But for now.. This is what I love. Some people are just built for it.