Two things:

1) Slurpies, like many things, are best straight from the tap. Ignore the store attendant when you guzzle your beverage right off the pump, he's probably just so excited you're experiencing your drink the correct way.

2) It has taken me a long time to adjust to living far away from a convenience store. I miss the freedom of getting a Big Gulp right when I wanted it, with maybe an impulse purchase of beef jerky I'll never eat.