Think we always calculate accurately every cost, every expense and every income whatever in personal or at our job. We could be savvy. But it doesn't work when we meet the one thing - 'Relationship'
Think about you and your lover going to have a dinner for your anniversary. You picked a nice restaurant, pick a bottle of the great wine and even yup, a wonderful gift for him/her. Believe me, your usual accurate and savvy calculation doesn't work at all. You tend to pay the above checks even they're a high amount. Why? It's a magical effect when people face the relationship and it produces the subjective feeling to affect your decisions. Does how much the check matter? Definitely. But how savvy as you will choose to grab it.
'Because I hope to give him/her a special and great moment with me.'
It's the answer to the cost of the relation is so high so that can't be under control. Every time you get your financial plan to hit the nail on the head but rarely execute it perfect. That's why.