Frustrated because they saw him as a new dawn and it did not happen. I think it was hoped he would be in the know and would attract a lot of decent players e.g. loanees from Liverpool in the way many thought we would be getting some Barcelona loanees when Garcia turned up. It did not happen...
Really don't understand the vitriol directed to both Scottish football and in particular Celtic (together with some poor comments about women's football). Celtic fans are passionate about their team and annoyed in the manner he left and that he did not deliver a lot of fans would feel that way.