On which topic or subject do you and your SO fundamentally disagree?

Spending and the accumulation of stuff: I’m a minimalist by nature, and more so since my divorce. All of my belongings could fit in a 8’x10’ storage unit - I know this because for a time they did. I left with only what I needed to rebuild my life and feed my soul…my tools, my books and music, my work clothes and a few household goods. I only buy what I need, and the few thing that I splurge on as an occasional treat - a good bottle of bourbon, dinner for us out at a good restaurant, a weekend away somewhere, a book by a favorite author. She spends frivolously in my opinion: clothes, shoes, lotions, decorative knickknacks that serve no actual purpose etc. All that’s fine, I suppose, if you have the income to afford it. But she doesn’t, and can’t seem to cub her impulses to spend.