Is it bad to let your baby/toddler dress how they want?

When I was little my mom allowed me to pick my own clothes. I wore the spunkiest outfits with my halloween fairy wings. I've always been raised thinking that its okay to express yourself as long as I'm not dressing like a hoochie. I always wanted to raise my child the same way. I don't mind my son wearing costumes. Maybe one day he decides he wants to dress like a cowboy. The next day he wants to dress like a fireman. What if he's a huge fan of where the wild things are and he wants a wolf costume like max? Is it wrong to let our kids express themselves? I'm just wondering if there's any other parents that think like me.