I might make a longer post about this later, but: Anti-Fest was awesome.
Do you mean a specific band or just concerts in general?
I have been to seven big concerts:
2009: Die Toten Hosen
2011: Leningrad Cowboys
June 2012: Zoči Voči, Horkýže Slíže, Billy Talent
August 2012: Nofnog, Radio Havanna, Anti-Flag
October 2012: Arkells, Anti-Flag, Billy Talent
April 2013: Wham Bam Bodyslam, The Forum Walters, Radio Havanna, Authority Zero
April 2013: Choose Your Heroes, Pocket Rocket, Nations Afire
And if I also count the smaller shows of local bands, I have been to about 11 or 12 concerts. Thank you for the question :)
I met Nik and Chris of Nations Afire earlier this week.
(by the way, the concert was amazing!)