It was really, really, really nice.
I've been a diehard work-from-home guy for ages. Why spend perhaps 10+ hours per week commuting? It's a productivity and environmental nightmare.
But... sometimes?
Yeah. It's nice to be in the room with other smart people, solving hard problems. I didn't realize I missed it until I experienced it again. For the first time in years.
I think it also helps team cohesion. We're human beings, not robots. I think my ideal schedule would be "3 days at home, 2 in the office" per week or maybe "one week in the office, two weeks at home."
edit: I'm baffled by the polarized and inflammatory replies to this post. I was just relating a personal experience. I don't have opinions on how others should work. You want to be 100% fully remote forever? Cool. I don't think you're wrong. I'll continue to be remote a majority of the time, myself.