I wouldn't say "mostly", but a good amount of them are quite serious, like for example 15th of March and 23th of October (in honour of the war of independence during 1848 and 1956, respectively), and a few smaller ones like 6th of October (in honour of the 13-16 Hungarian officers who were executed for playing key roles in the one happening in 1848). On the opposite end, the 20th of August (in honour of the nation's establishment) is a rather happy one: the smaller villages like the one I live in kind of "divide" it in themselves who is going to celebrate it on which day in order to let people visit as much celebrations as possible (for the MONEEEEYYhhh, of course), but Budapest and bigger cities always hold the celebration on the 20th. The bigger cities of course always attempt to make this celebration big with many, many options for entertainment, but in smaller places like mine, it's pretty much just a good opportunity to let people have a good time with their families and friends. Kind of like the 1st of May (a.k.a. Workers' Day) really, except the 20th of August celebrates a much more important part of our history.