When you spend the whole fucking day waiting for a colleague to finish something that is blocking the whole team.
He finally finishes at 5:30pm and goes to home.
I just left work at 9pm.
He's a nice guy but gosh he can be slow sometimes.

9PM, overtime but no pay - dude, I'd call your colleague simply "smart". That's how you react to such incentives.

Yeah, I would have been out the door long before he finished. If everyone accommodates him, his behavior won't change.

Leave at the time you stop being paid. Also, a dev is stuck? Fucking help him, that's what working in team means.

I can't see how a task can be blocking like this

To clarify a little bit.

Our project is based on a really really bad infrastructure. We have a denormalized database which is different depending on which client we are deploying for. Which means that if someone is working on a feature for a certain client A and load its config on the database anyone else working on something for client B is blocked.

We currently don't have much other choices than working that way but we are working on a complete recast of the project. (basically throwing everything and restarting from scratch)

He wasn't having trouble on his feature, I was just slow doing it therefore blocking everyone for a day