I've just been offered a new role in the same company so will be leaving my current job.
Thing is I've never really gelled with colleagues in the old job, I can work with them perfectly well but wouldn't go out with them outside work.
There's a culture of a team collection to buy a gift and card and go out for drinks on the last day, but I don't want any of it. Everyone's got better things to spend their money on and the thought of a gift presentation in front of everyone makes my blood run cold
I just want to finish work as normal, say goodbye and go, that's it.
If I'm not BU how do I go about it? 
I've run the idea past friends and been told I'm boring or ungrateful.