When you start getting really serious about retirement savings, you'll understand why a difference of 0.50 cents per day v.s. $3.00 per day, is actually a big deal.
Enough of those differences, and things start to really add up. Enough things add up, and you realize that money could have been making you ~8% in an index fund for the last year. Suddenly, the iPhone, the multiple Starbucks, the BMW, the designer clothes... all things rationalized as "just a few bucks a day" ... end up costing way more than that.