It's their job to endure the discomfort of having to do the job they're paid to do. It's not your job to make it comfortable for them. That's not to say that there aren't personal or professional consequences for how you conduct yourself. Burning bridges and all that. But I feel that's completely up to you.
It takes a special kind of company for counting it as a burnt bridge for somebody that said "I hope you all fail" and gone away after being fired.
As a rule, you shouldn't burn bridges.
But in some occasional cases, the bridges you burn light up the way forward.