Can I give a tiny bit of sugar to my 8-week-old puppy as a training reward?

No, you should avoid giving sugar to a young puppy. While not toxic, sugar provides zero nutritional value for a growing puppy and can set up poor dietary habits, contribute to obesity, and harm developing teeth. A puppy's small size also means even a tiny amount has a bigger impact. Stick to puppy-specific treats or tiny bits of their regular kibble for training. If they accidentally ingest some, just watch for an upset stomach and consult your vet if you're concerned.