YMMV, but I got great returns on investing in a proper chef’s knife, and learning how to use and maintain it properly. There’s a real pleasure in dicing an onion or whatever in seconds. Knowing I can do that helps lower the ‘activation energy’ of cooking versus takeout, as does just generally loosening up about cooking.

My favorite meals are often thrown together in 20 minutes with zero planning, and certainly no recipe. Knowing a few fundamentals (see Salt, Fat, Acid, Heat) gets you a long way.