I'm not sure I agree with that. There's always colleagues and then there are friends. There are colleagues who are friends too. From my experience the corp world is good to you upto when you are useful for them. In startups that I've worked for I've seen the 8-5 schedule go out the window and your life's ruled by deadlines and bugzilla lists. That said, the point where people reveal their personalities is the point where most snap or think, damn the consequences. As much as we are emotional animals, it doesn't make sense to be an open book. In fact it might be something which other people take advantage of. Again most corporations have a 20-80 ratio where 20 percent of the people do 80 percent of the work. Though this work share balance might be better in startups, it pays to be on guard at work and keep notes about everyday accomplishments. I've seen really hard workers get fired while those who politick stay employed. While startups are in the gold-rush phase, during hard times, co-workers turn into Gordon Geckos, especially during layoffs, so a teflon attitude is a worthy defense.