And to further confusion - if you hear "diä hämmer dänn gärn" (hard to translate, something like "don't we just love those"), it is NOT a term of endearment, but an insult. Imagine you organise something and ask everyone whether it's ok, they all agree, but one, who insists on changing everything. That's when you say "diä hämmer dänn gärn!".

Another variant is when you give someone an unpleasant task or say something playfully insulting to a friend, then that person may reply "ich han dich AU gärn" with an intentionally pained smile. It's a sort of reverse psychology thing, the reasoning being that if you liked the person, you wouldn't do/say what you are doing, so you sarcastically remark that you are fond of them too - not. This is very informal though.

And then there is "Weisch was? Chasch mi gärn ha!", which is basically "You know what? Screw you!".

Ich hab dich lieb is distinctly High German but us Swiss are increasingly letting the lingo of The Large Canton (aka Germany) permeate our Helvetic tongue. Which is a shame, there are some brilliant Swiss German expressions...