There are fewer more distressing sights than that
Of an Englishman in a baseball cap
"Time for Heroes" The Libertines
I like baseball caps. A lot. And even though I recognise that there's a good argument for only wearing the cap of one's preferred team, there are and have been too many beautiful baseball caps to limit my head to one team.
I do, however, make sure not to buy caps that are not the team in question's true colours. That is: no red Yankee caps, etc.
Since 1 May 2009, I've been keeping a note of which baseball cap I've worn every day. If I wore more than one cap during a day, I've represented the one worn for the most time.