When I was a 10 year old kid, and you had asked, I would have told you that Psychic was my least favorite type. The weird, humanoid trending designs was really off-putting. I remember really disliking Kedabra, Alakazam, Mr. Mime, Jynx, Exeggutor, and several others.
After leaving Pokemon for a long while and coming back as an adult, I found my tastes had changed. Psychic is now probably my fifth or sixth favorite type now. Quite the reversal from holding the absolute last spot.
Have you had any types which you originally hated but came to love? Or any types you loved which you came to hate?