I honestly have done this for the endorphine boost, but overall I’ve lost just under 11kg in about 10 months and I’ve really started to notice my belly go down, and I can actually see muscle building now... which I’ll be honest and say surprised me (why I have no idea). This is great, but I did exercise to deal with some pretty appalling trauma I experienced - everything else is nice but for me, not essential.
People start way too intense, spending hours in the gym, and burn out all their enthusiasm in the first weeks or two before they realize that their efforts are unsustainable. Really, start with a plan on what do to, go in and do it. If it's a half hour that's perfectly fine. My sessions, depending on the day, last anywhere from half an hour to 3 based upon my mood and the workload for that particular session - but you gotta keep the mandatory work to a reasonable amount - everything else should be treated as icing on the fitness cake.
I'm sure to go with the 11 kg there has been significant body composition changes to make it count for more as well.
Likewise for diets. Those who spend their New Years resolution momentum eating baked chicken and broccoli for a week or completely cutting out carbs will shortly find themselves failing completely and binging ice cream or whatever. Rarely do you see sensible advice like "keep your same diet habits, but cut out soft drinks", or "if you engage in late night boredom-eating, try binging vegetables instead."
Unfortunately, humble and incremental changes in habit seem antithetical to our society's affection for (unrealistic) sweeping, dramatic transformations.