Goodness. So many things.
I'm lucky enough to have the time to cook, but I honestly don't like "cooking". I can't stand the thought of being in a kitchen for hours on end watching the clock to bake something or performing unpronounceable techniques to get food "right". I struggle with making healthier foods that don't make me bored to cook.
Starting exercise. Once I begin my walk or start my movement I'm fine. But the moments leading up to that point... I drag my feet a little...whine in my head that I don't want to... I really have to push myself to just start it.
Lastly, the scale. Hopefully by the time I do actually reach my goal weight (years from now in all honesty) I will have accepted that the scale will do what it wants, and that as long as I focus on the positive and keep "health" as my goal and not "weight" then the pounds will eventually come off. Still... I'm human, and seeing the scale stall or not move as quickly as I like makes me testy.
Those are the big ones for me. Despite everything, it's so worth it.