I feel like someone always chimes in to say this, but the underlying assumption here is that a significant portion of one's social fulfillment should come from their office workers, which I think is ludicrous.
Let's be real here, what percentage of people - especially engineers - really find that their social needs are being satisfied through their office jobs? After you or your co-worker leaves their job, how many ex-coworkers do you actually still remain in contact with?
I've always found office relationships to be fairly boring. Because they're you're co-workers, you have to keep a certain level of professionalism and political-correctness so as to avoid offending people. This basically confines the realm of acceptable dialogue to banal things like the weather and small-talk. If you want to say anything interesting about anything interesting like say politics, you basically have to first probe them to make sure they're not going to get offended and passive aggressively retaliate. Anything you do outside of work like a cool side project or that band you're in can't be seen as threatening to your dedication to your job, so it's safer not to bring it up.
And I'm prob going to get a lot of flack for this, but I think most office workers are fairly boring - going to work, going home to their significant others/kids, and waiting to retire. Or maybe they're really interesting but don't feel comfortable talking about interesting things at the office for the reasons I mentioned above.
Ultimately I think it's better to find social fulfillment on your own and not expect it in the office, otherwise you're bound to be disappointed. But I get that it's unfortunately hard to make friends after school. I think there are a lot of reasons for that, but that would require another long post that's outside the scope of this comment.
EDIT: Just after I posted this I see this on the front page https://news.ycombinator.com/item?id=21274511#21274909 Kind of supports my thesis.