Many floating voters decide after asking what's in it for me , I agree sensible but many who stay with a party asks what's in it for the vulnerable
So, in essence, you are stating that most floating voters are selfish people who only vote according to what's in it for me.
I did not say that at all, but if you wish to interpret it like that, that is up to you.
Personally (and I am sure many others) think 'what is best for the country as a whole, bearing in mind that we need a sound economy, jobs and a good welfare system to protect the vulnerable and look after the sick.
When a government goes too far in reform one way or the other, I know people who think 'Whoa, no, I will vote for the opposition next time to bring a bit of balance back'.
If neither appeals then the Lib Dems are a good balance. 
At the moment most of it is a load of old bollocks chaos and I have no idea what I would do if there was to be an election shortly.