Abide?
Only if you’re The Dude.
But you could feel indifferent towards opera, or, better yet, be ambivalent about opera, both of which are valid constructions.
Still, point is taken, that it appears that a verb is what is being sought.
Actually, “tolerate” is almost there. It still has a negative connotation, rather than the purely neutral feeling we’re looking for, but “I tolerate opera” is getting closer.
emphasis mine
I thought we were concerning ourselves with words. If we’re going to worry about connotations and feelings we’ll never find a neutral word. I wouldn’t go so far as to say that connotations cannot be neutral by definition, but by the time you have one nailed down it’s likely to have changed.
That being said, ‘tolerate’ has a built-in connotation; the object of toleration is viewed negatively.
Abide, on the other hand, is often used with, can’t. (I can’t abide a list with fewer than three items.) It’s a bit like the saying: I couldn’t care less. The negative connotation is in the construction of the sentence. Saying, “I could care less,” really means nothing more than, “I care.”
By using abide alone, the only negative connotation comes from faint praise.