Baseball card collecting is not a warm-weather hobby
Who wants to be thumbing and sorting through cards, when it is so nice and sunny outside? Pity the fool who would rather be inside playing with his cards or has no other 'default' choice, other than to flip through his brick of useless commons.
I can't come up with a collecting theme that compels me to be focused [with time, effort and $$$]. All my cards and other stuff are 'housed' in my room and it is hard to be enthused with anything when your abode is a furnace for much of the late afternoon.