That would be a big negatory.
My older brother finally left a job he'd had for 15 years b/c he was in one of those situations where he did all the work around the place, made it possible for his boss to do very little work but still look good to his bosses, so my bro wouldn't ever get promoted because the boss needed him too much where he was. You can imagine the frustration of being punished for being too good a worker. So he just flat out quit one day without another job and cashed out his 401K to "pursue his dreams". That was about five years ago.
Today he's back doing another job he dislikes because he blew through his 401K faster than expected, and has a family that depends on him. He's struggling to rebuild a 401K for retirement, starting from $0 , with not much extra income to put aside. He talks all the time about how it kills him what he did, and how much money he simply flushed down the toilet to penalties/taxes. Believe it or not, he's STILL dealing with tax issues from this due to not understanding how he was supposed to handle it when he cashed the 401K out.
But to be honest, even if I didn't know that story I'd never do it except in a dire emergency. If you want to go to school, there are student loans, scholarships, and programs for working students (DH is in one). If you want to pursue a dream, then figure out how to do it on the side until it shows some sign of being able to support itself (or up your retirement funds now so you can retire early and spend all your time doing it). Feel like helping orphans, volunteer.