Let me guess: your native language is Germanic, Romance or Slavic.
Esperanto's phonetics, phonotactics, vocabulary and grammar are all overly Eurocentric and twice as complicated as they should be for a language that is presented as a tool for global communication. And don't even get me started on diacritics.
Anyone who grew up speaking a non-Indo-European language is going to have a hard time even getting the hang of the alphabet and all the sounds.