I always brush my teeth after breakfast. I don't like all those little bits of stuff stuck in your teeth after you eat; it really bothers me. If it's bothering me a lot, I'll brush and floss after any meal though.
I brush them after because if I brush them before I eat, it'll make my food taste weird. And what's the point of brushing them before if you're going to get them dirty again???
I brush my teeth as soon as I wake up because we have morning breath, and I eat some time later. If i'm going out, I have a little brush tool that can use to pick out the food out of my teeth or I just brush slightly because brushing your teeth after eating is bad for teeth since it can possibly damage the enamel depending on what you eat and how soon you brushed them after eating
Edit: I usually eat about an hour or 2 after I brush my teeth since sometimes eating asap hurts my stomach
I can't brush my teeth right after eating because it makes me gag and sometimes throw up. After I eat, I chew sugarless gum or eat a mint. I can brush my teeth a couple of hours later.
I usually brush my teeth after I eat my breakfast but sometimes I brush my teeth before. On weekends I brush my teeth after, on school days I brush my teeth before since it's a big hurry as my bus comes at 7:30 am when I wake up at 7:00 am.
You are supposed to brush before breakfast and use mouthwash afterwards. Brushing after breakfast means your teeth will get worn down by the brushing after the sugars etc soften the enamel from breakfast.
Brushing BEFORE breakfast strengthens the enamel after sleep so that when yoyoueat breakfast it won't damage as much. Mouthwash then just clears any loose debris.