Something I have a major problem with is people who are on their phones or smoking while driving.
Now, I can learn to drive in September, but I wouldn't feel safe learning when so many people are on their phones and driving.
I'm in the UK and this is illegal but it just happens so often, just yesterday I was with my mum and we saw 3 people on their phones and they weren't driving properly. These people had vaguely new looking cars and phones, so they clearly had a bluetooth feature they could have used so they could drive with their two hands down a tight road (cars parked on either side of the road. Eh, common thing here) and not almost crash into us.
I also have a problem with people picking their noses in public, it just grosses everyone out, at least use a tissue. And the other week I saw someone who looked about 30-40ish picking their nose at a bus stop... and eating it. Eugh it made me feel so sick.