Well I mean there is the history behind it....kind of like how no one really celebrates Colombus day anymore (3 day weekend is nice though). HOWEVER if you focus just on the fact that family gathers in one place for one day full of crazy amounts of food and make it a day just about that, yes, it is nice. I won't celebrate it for historical reasons, the reasons to enjoy the day are just family ones and the fact it is a day that hasn't been commercialized is a bonus. Again, in that case it is for sure a fun day with lots of beer.
Cinco De Mayo is not a holiday
No it is not and it is not celebrated in Mexico either.
I like some of the holidays from other countries like dragon boat festival and spring festival in China. Also, Chinese new year in China is an absolute s***show, mostly in a good way and so different from outside China. Day of the dead in Mexico is really interesting and likely not what most people envision. holy week, especially in Colombia, an entire week off in late March or early April...colombia has something like the 2nd most holidays in the world and it was nice to get so many three day weekends. music day in france is likely seen as a holiday at this point is an absolute blast the first day of summer and I know there was one or two cool ones I celebrated in Guatemala.