Do low quantities of alcohol affect your mood?

I had a beer last night for the first time in about 3 months. I didn't consciously choose not to drink in that time period, I'm not an alcoholic, nor have I had an alcohol addiction in the past, I've just drunk less and less over the years since having kids. I go months without, and usually only drink a glass or two of wine or a couple of beers when I do.

I have nothing particularly against alcohol in moderation, I appreciate how a fine wine can complement a meal. However, I noticed today even after that 1 drink yesterday, that I've had less patience with my kids, even snapped over what normally wouldn't bother me so much.

I wonder even how small amounts of alcohol can affect mood and brain chemistry. Or am I just more sensitive. But it's got me thinking.

So what's your relationship to small amounts of alcohol and how do you feel about it? Those who drink in moderation, do you feel better when you go for long periods without?