Pretend, for a moment, you are Jeremy Renner. You're in Houston for a comic convention, because you play a superhero in a wildly successful Marvel franchise, and because you wouldn't be in Houston for literally any other reason. You happen to stumble to upon a wedding with an open bar, and you, being Jeremy Renner, decide it's best to crash it, perhaps without thinking of the consequences. You mentally calculate that this is probably totally fine. You appear moodily at the bar, trying to rest your weary brow—but too many people try to talk to you, and you end up leaving after 15 minutes. Well, you don't have to pretend any more, because that all actually happened, and no one was the least bit surprised.
TMZ reports that the wedding guests (who were just excited that Renner was there) said Renner was "standoffish" and refused to take a photo with the bride and groom. Again, we're shocked. From TMZ:
...we're told he was actually kind of standoffish with most of the guests ... and even refused to take a pic with the bride and groom! [...] But actually, Renner tells TMZ, he was hiding at the bar to avoid upstaging the newlyweds
How kind of him! I guess not crashing the happiest day of someone else's life was probably not an option. That's okay. Renner told TMZ that after he left, he "went off to enjoy the sights of Houston," which is a totally gracious way to exit, and not sarcastic at all.