Hmm. For me, it would probably be
1. Climate. It's too cold here for about five months out of the year to wear anything stylish.
2. Money. I don't have enough money to afford things that I really want, so I have to wait until something similar is offered at a lower price point. But I don't give up.
3. Health. It takes too much energy to do my hair AND do my nails AND put on makeup AND put on a good outfit (which is why I focus on the last).
4. Self-consciousness. It is hard to dress up in something quite different from what people are used to seeing me in. However, I do take small steps in this direction toward my fantasy style, and maybe someday I will get there.
5. Life events. Part of the fantasy me would involve dressing up in wear that is good for parties and other social events, but my health situations prevent me from going to such places. C'est la vie!