Why are some buzzes better than others?

I'm not talking about tolerance or anything, or taking long breaks. I mean sometimes I'll only go for 2 hours without it and then buzz will be really good. Sometimes morning buzzes are monumentally greater than others despite the fact it's the same amount of hours taking a break.

Makes me think there's more than just time affecting nic buzzes. Is it affected by what you eat, how much water you've drank, etc.?