I left Barcelona just yesterday after my second visit to the city. The first visit was many years ago, and it was barely a visit as it was a day trip from Calella where I was playing in a handball youth tournament with my team. We basically arrived, went to a pub, and stayed there until it was time to head back :)
This time around I explored the city by foot and public transport during two days. Barcelona is a very fun and lively city! People are out and about, and it is busy in many of the central parts even with less tourists during what is currently (hopefully) the end of the COVID-19 pandemic.
Even though it is big and busy, it feels pretty relaxed. And it is great that the city stretches all the way from the green hills to the beautiful ocean. We went to the Barceloneta Beach which was nice and convenient.
There are a crazy amount of yummy options for food, and many things to see. We walked up La Rambla, visited Park Guell and Sagrada Familia, but most of the time we simply wandered around and stopped at small restaurants.
Barcelona is very pedestrian friendly with wide sidewalks even on busy boulevards, and public transport worked very well. I really liked it, and will be back!