Also, a lot of habitual users are self medicating and potentially without realizing it, since weed for some reason isn't a part of the medical system. So, when you stop you can get hit with hardcore depression, panic attacks, extreme anger management issues... but that is dependent on the individual. Those things were there to begin with, and having been masked for so long, they come back with a vengeance. That part almost reminds me of my heroin use because I have been medicating several health problems which make it tougher to stop.
The only real physical symptoms I would say are possible severe appetite suppression, nausea, insomnia (I consider neutron down regulation or chemical imbalances physical too). It can still really suck, but one should be happy that they can at least get out of bed, and the suffering is nowhere near unbearable. If someone is struggling to quit and they want to it's mostly due to drug cravings similar to cigarettes if they smoke all day every day for years, or mental illness in my opinion.
When I stop smoking my panic attacks and insomnia come back with a vengeance and it totally sucks. It's just not heroin or benzo withdrawal; my life isn't at stake and I can deal with that shit. When I run out of weed, it doesn't mean two weeks of extreme brutal suffering that is mainly bedridden before I can even begin to stomach food and take care of myself. I can still hold a job.