Another problem that many players don't even consider a problem in the transition from regular work to poker is the lack of a real social environment. Most often we have to sit alone for hours in a closed room, alone with the monitor.
For me personally, this has never been a big problem. I'm a pretty independent person. But I know people who are really depressed by this loneliness.
Many people like to "crackle" at the cooler in the office or just chat with colleagues right at the workplace. As a professional player, you won't have any of these. Even if you play in a casino, things will be different, because poker is not a team game. Each player at your table will be your opponent.
Thus, for me personally, professional
online poker is hours spent alone with music and a monitor.
Again, this is normal for me, but not the fact that it will be normal for you. If someone is serious about quitting their job, be sure to consider this factor.