Your subject mentions UCD and UCSD but you’ve posted in other threads that you didn’t like UCD. Is it just down to UCSB vs UCI?
UCSB has a college town and is a more traditional college experience than UCI. UCI tends to be pretty quiet on the weekends as a lot of people go home. UCI is divided into several colleges. Double check that your priority registration applies to all classes in all colleges or just the college of your major. Three years ago when we went to the honors open house, they made it clear that priority registration was only for the classes in the college of your major. Things could have changed since then so please verify with the school.
There is a lot of partying at UCSB. I don’t think the kids who don’t participate feel uncomfortable. They find friends with similar interests and arrange other things to do on weekends.