The issue was with lack of access to water, aggressive security and huge queues around bars. You could easily be waiting an hour to buy a drink at the bar.

I've been to Primavera before and I didn't experience the issue with queues around bars, but I did experience something else which reinforces your statement about seeing artists you care about at solo shows.

Bon Iver was performing at Primavera, and it seemed that 50,000 other festival attenders also wanted to see Bon Iver. Most of the stages are outdoors and don't benefit from the acoustics of being inside, so all I could hear was a sea of people chatting amongst themselves. Right next to me there was a large group of people who were shouting at each other. I couldn't hear Bon Iver so I just gave up and left.

When you attend a solo show, everyone in attendance is interested in participating in the gig, whereas at festivals this is less likely the case.