Part of the reason some people think mushrooms taste the same is because many common supermarket mushrooms in the west do taste similar.
In particular, three of the most common western supermarket mushrooms (button, cremini, and portobello) are actually all the same species (Agaricus bisporus). They just look different.
Shiitakes are a different species and do taste different, but are somewhat related; at one point in the past they were classified in the agaricus genus.
Once you venture outside those, tastes and textures rapidly diverge. Truffles and morels are definitely memorable if you've never had them before.
In particular, three of the most common western supermarket mushrooms (button, cremini, and portobello) are actually all the same species (Agaricus bisporus). They just look different.
Shiitakes are a different species and do taste different, but are somewhat related; at one point in the past they were classified in the agaricus genus.
Once you venture outside those, tastes and textures rapidly diverge. Truffles and morels are definitely memorable if you've never had them before.