I started smoking weed in College. Since then, I've developed a habit of smoking almost daily. Not all day, but usually a few tokes from a vape at the end of the night.
When people ask, I usually reflect that weed has been a very positive addition in my life.
I became VP of Eng. for a well known software company within 3 years of graduating. We did a lot of things right and the company eventually exited with unicorn status. I then left, bootstrapped my own startup w/ a small team, and after 2 years were acquired by a major software company which cemented financial independence. These days, I spent most of my time doing advisory/consulting/investing roles.
I achieved all of this within 10 years after graduating, AND essentially consuming weed daily(usually took breaks when traveling, etc.).
For me, it helps me with relaxing as well as creative thinking. The way I describe it is that it removes mental filters and allows you to appreciate something in a new way (that "mind blown" feeling). Sometimes the insights can be superficial, but sometimes they are not.
Nowadays, I am generally pretty open about my use when people ask. What I've found is that it is a lot more common then I used to think. So many founders, executives and otherwise "smart" people use it frequently for mostly the same reasons. I'd have never guessed.
For anyone who might be interested, I'd suggest reading Carl Sagan's essay on it in which he talks about his experiences and insights while high. He actually wrote it under a pseudonym (Mr. X) but revealed his identity through a friend after he passed. http://marijuana-uses.com/mr-x/
This is also just my own opinion - but from my own experience what I've found is that people tend to want to blame someone (or something) else for their problems in life. And generally, marijuana is a pretty good scapegoat to point a finger at.