[MWeed]

No it'll probably piss them off as they've already asked you what they wanted to ask you based on your long application form.
If you go back and, yeah you could end up with a "different" big brother in the diary room but if you feel it didn't "go well" and you answered questions about yourself and your life, and you go back and act differently they will not be interested as you aren't being yourself one of the times.
Also, there is the chance that this time you don't even get past the picking pens.