True. For our startup we experienced the same; we were working with a team of 3 and we could just camp out at one of our houses for a week and do dev'ing during the day and relaxing/drinking in the evenings. When we hired a 4th guy to help out these weeks turned from awesome and productive to a sluggish pita week. He produced great work but hanging around with him in the evenings was more stressing and tiring than all the work together.