Parking on J St during baseball season
There are very tiny, very confusing, and very poorly placed parking signs that tell you the date and time of all the Padres games, when your car is almost guaranteed to be towed. But even if you can decipher that code, parking downtown is going to be a chaotic nightmare on a game day no matter what. You're better off Ubering, or parking in another part of the city and catching the trolley downtown. When the game's over, find a bar to wait out the rush.