Uhh, I couldn't imagine only getting slightly drink all my life. There's a difference between drunk, and drinking too much.
for me, there's something like this:
1-3 beers: Basically feeling nothing, unless I haven't eaten all day.
3-5 beers: definitely feeling something, either slightly buzzed, or heavily buzzed, depending on whether I ate a lot, or not much, and how fast I drank them.
5-10 or so: Drunk, by 10 I'd probably be bordering on having drank too much.
This is not completely accurate, because the only time I got to 8 beers, I'd been eating while drunk, and then I ate a bunch of hot peppers, which really upset my stomach, and I also had nothing to eat for quite some time before we started, and we were drinking quite quickly.
Recently, we've been ordering pizza a lot when we drink, and I usually fill up on pizza, which means I drink about 5-6 beers, and I'm full, but because of how much I ate, I'm still only buzzed.