Prison sucks and it's not meant to be a good place to be.
The worse part I would say about being in prison is the fact that you're stuck there for the amount of time you have to serve.
Your freedom is taken away and you have to do what the guards tell you to do and you risk getting harmed or killed by other prisoners.
In prison you do have to watch your back every minute or something bad could happen and although not very common you can get raped inside of prison.
Imagine your life now where you're free now and can walk out your door anytime you want and go do anything you want?
Well in prison you cannot do that and imagine having a 5 to 25 and even 30 or even 50 year sentence or a life sentence and you having to stay in that same place 24 hours per day 7 days per week until your prison sentence is up or until you die.
Most times a prisoner serves out their entire prison sentence at one prison and is not moved that often unless their security classification changes.
Also imagine if you were in a high security prison such as ADX Florence where you're locked in a small cell and have to stay there for 23 hours per day with one hour per day out of the cell and into a rec cage for a bit of fresh air.
That would suck even more and prison and I mean no prison is a place you should want to ever end up.