Oh, yes, I know what you mean. I guess the biggest one for me is
Geoffrey.
Love Geoffrey but I loathe loathe loathe
Geoff, and have a really bad association with a
Jeff. But as it's the first syllable of
Geoffrey I know I'd end up calling him that, it's automatic for me to shorten a name to it's first syllable. So
Geoffrey is out.
With
Alice, neither of those seem like automatic nicknames. If anything, I'd be worried about calling her
Al cause that's what I would automatically call her. I think nn's can be avoided if you really want.
Alice is a lovely name.