I've seen so many men wearing such different blazers in a variety of occasions and i love it. I don't think blazers only belong to suits. Personally, i love to see it even more on a casual look.
I think it's a versatile piece of clothing. You can wear it to a meeting, weeding, date, going out. Everything. I love a man with a blazer, eheh :)
Here are a few examples on casual looks:
And here are some in formal looks:
What do you think about blazers? :)