It's probably a physiological thing. Out bodies store fat for times when we need energy but can't get food. In this day and age though food is everywhere 24/7 and most people (in north America at least) have access to it. Not only that, there is a lot of stuff in boxes and in fast food masquerading as food but is filled with extra fat and sugar and calories so it tastes 'good'.
Losing weight becomes easier, it's about breaking bad habits, making good ones, and changing your tastes. Believe me, after a while of no high fat food your body will reject it if you try to eat it. It's about making gradual changes so it isn't so hard.
Personally, I never thought gaining weight was 'easy'. Mentally it was the worst thing ever. Such a feeling of being out of control, and binging for no reason. Living healthfuly is so much less stressful, because even if I'm not losing weight, I know I'm treating my body right.
"Courage doesn't always roar. Sometimes itís the quiet voice at the end of the day saying, I will try again tomorrow."