[thothamon]

You founded the company. So take control.

Set 6 pm as the going-home time for EVERYBODY. If something is late because of this, that means the company should not have made commitments it can't keep (and you should take a strong interest in not making the same mistake again).

As someone said, don't answer the phone past a certain time. Most phones have some kind of do-not-interrupt mode. Use that. If people have an emergency, at the very least they can call and leave voicemail.

How about bringing a refrigerator and some beers into the office? Lead by example. If you're drinking beer at 2 pm, that tells everyone else this is the kind of startup where drinking beers at 2 pm is OK. People who are too uptight to deal with that will leave: let them.

It's _your_ startup. Run it the way _you_ think is best. What's stopping you?