Martin Allen accepts that some Barnet fans will not welcome him back to the club after he left to join Notts County last season.
Allen, who left Underhill to join the Magpies, has returned as manager for the climax of the League Two campaign after the Bees parted company with Lawrie Sanchez on Monday.
Allen had been re-appointed as Barnet boss in March last year for the last eight games of the season, but left to join Notts after just three games at the helm.
He told BBC London 94.9: "I can understand the supporters were upset last year. It was a very, very difficult decision to leave.
"For the people who've criticised me, Barnet is the love of their life. For managers, it's a job. If better offers come along, generally people take them.
"The public have a general conception if you're a football manager then you're absolutely minted - I'm not."