I've been watching a few episodes from Series 1 of Friends, and its funny the little differences that were changed in the later series.
The View out of Monica's large window is different. Monica and Joey/Chandler's door number (4 and 5 instead of 19 and 20?) Gunther has a different name, and does not speak Ugly Naked Guy's apartment is in different direction from the window. Rachel's mates *do* know where she is, where as in S7E20 "Ray Ray" has been mission for the last 7 years.
Anyone got anymore?
Also (as to be expected) the characters are slightly different as they haven't been developed yet, but Joey seems slightly more intelligent, no mention of his "How you doin" yet (what was the 1st Episode that was in?). Monica seems a little more laid back, and Janice isn't as loud...although she seemed to get louder and more annoying every episode she was in...which was possibly the idea!