Just an observation.
Ted was originally modeled on you, and Marshall on Craig. How far have those characters evolved from that? Do you ever sit around and say, "I wouldn't do that" or "We wouldn't do that to each other"?
Ted certainly isn't me anymore. I haven't been engaged, or had a lot of the other experiences he's had. It's more the characters have become themselves .We definitely do try to ask ourselves, "Would this happen to us? Would this happen to someone we know?" for all the characters. We try to keep them personal and real, but there's more overlap now. I relate to Marshall as much as I do to Ted.
Full text here, but it is spoilerish for the last ep of the season.