Do Burmese cats make biscuits more aggressively when they are happy, or is that just individual spice?

It really depends on the cat's personality, but Burmese cats are known for being extra expressive and intense with their affection. I've seen some Burmese who knead like they're trying to punch dough into submission, especially when they're purring and drooling with joy. That said, I've also known laid-back Burmese who do it gently, so it's not a breed-wide rule - it's more about how each cat channels their happiness.

I'd gently push back on the idea that it's tied to happiness levels. In my experience with Burmese cats, the kneading intensity is more about their individual personality and early kittenhood habits. I had a Burmese named Mochi who kneaded ferociously on any soft surface, even when mildly content, while another I fostered was always gentle. It's like people - some give enthusiastic hugs, others are more reserved. You're better off observing your cat's specific quirks than assuming a breed-wide emotional trigger.

My male Burmese Theo kneads hardest when he's settling down for a nap, not necessarily during peak excitement. He saves his most vigorous biscuit-making for right before sleep, as if he's testing the mattress. His sister Pearl, same litter, barely kneads at all, so it's definitely a personality thing more than a mood indicator.

I've owned three Burmese over the years and found their kneading styles completely unrelated to happiness levels. My first boy, Simba, would knead my stomach with the force of a tiny jackhammer whether he was purring contentedly or just mildly annoyed I was five minutes late with breakfast. His sister, on the other hand, only kneaded softly when she was already drowsy and calm. It's more like a personal trademark than an emotional barometer.