Small food challenges

So, I've never been a big water drinker. I try when I'm in my hard core tracking mode, but it usually only lasts a few days. So I'm trying to do it little by little. My hope is that when I finally make drinking water routine, I won't be as prone to drinking diet sodas or specialty coffees (won't be giving up my regular coffee though).

I won't completely give up foods/drinks I love because I feel that hinders my ability to do well on changing my lifestyle...and because I'm changing my lifestyle I want to incorporate the foods I love into my daily life. I am just learning to limit how much I'm eating of it.

So what's your vice? What is your hardest obstacle foodwise?