Such losers are aplenty in the working world, don't quite understand their mentality also. Every day they just sit around passively whining about being underpaid and do nothing but wait for someone "in charge" to give them more money.
When they finally quit, suddenly like want to salvage a shred of false dignity by acting rudely to the boss or HR to show "they are the biggest now". Worst thing is during notice period cause trouble for colleagues by deliberately sabotaging work or incessantly boasting about how "brave" they are in front of the boss now. End of the day people like that go where also at the bottom rung, the problem lies with them, not the boss or company.