Its syntax strongly favors cuteness over familiarity. Wherever Ruby can diverge from expectations to give you a pointless little tickle of whimsical inventiveness instead, it seems to do so.
Visually it looks like an unwanted love child of Pascal and Python. There's no clear rhyme or reason to the use of sigils and keywords.
The standard library and built-in types are acceptable for a mediocre '90s scripting language, I guess. The difference between symbols and strings as hashmap keys is a footgun that opens up endless bugs for the type of glue code that you'd often be writing in Ruby.
Probably the only thing that keeps Ruby afloat is Rails, an extremely resource-intensive web server framework built around assumptions of what web apps were like in 2003. Everything in Rails seems to happen by pooping magic keywords in your code or in file names according to mysterious conventions, so when something goes wrong, you'll have a hell of a time figuring out why Rails isn't calling your code or is generating broken SQL. OTOH it honors the Ruby tradition of doing lots of unexpected and useless cute things like pluralizing words in your database migrations [1].
[1] https://stackoverflow.com/questions/1185035/how-do-i-overrid...