What is easy to spot but hard to find?

Question

I'm a word that's easy to say,
But sometimes it's hard to convey.

It's not just a phrase, nor an expression,
It's a feeling that's hard to mention.

It's something that you feel in your heart,
And it's a feeling that sets you apart.

What am I?

Answer 1

A bug in a programs code, True love, Ghost, Talent, etc.

Answer 2

Identical Twins