I (30F) got married to the love of my life late last month. My husband (30M) has a younger brother (28M) who is very, very kind and sweet, and he's got a bit of a shy-puppy demeanor to him, which is really endearing. The only problem is that my BIL has a rather angry RBF. His eyebrows are always furrowed, even when he's smiling, and his neutral face has him looking pissed off and unapproachable.

During the wedding reception, I was sitting at the table with my husband and his my family members, and my BIL was sitting across from me. He was just sitting there, looking angry as fuck as usual lol, but I know that that's just his normal expression. I thought to myself that the other guests may be kind of scared by his expression, and so I cheerfully told my BIL to "turn that frown upside down!" My BIL started smiling and he laughed, but then he fell right back into his RBF. So I reached across the table, and I said "come on, now" and I used my index fingers to force the corners of his mouth upwards. My BIL sort of freaked out, and he squirmed and pushed himself away from me.

Later that night, while my husband and I were in bed together, after the first day of officially being a married couple, my husband brought up the little thing I tried to do with my BIL's mouth. He let me know that that was kind of weird, and it made him and his brother really uncomfortable. I told my husband that it was all just a joke, and it was nothing serious, but my husband got a bit incensed, and he bluntly told me "one: don't touch my brother, two: that's just how he always looks, and there's nothing wrong with that, and three: don't touch my brother". That shut me up real quick.

AITA? I still feel as though it was all just a joke that everybody's overreacting about.

EDIT: Wow, um, didn't expect this to blow up. I was gone all day because I was flying for a work trip, so I only now got the chance to read the replies. I just need to state that I had no bad intentions when I touched my BIL! And, well, my BIL always looks likes he's actually trying to frown as hard as possible.....he's a perfectly nice guy, don't get me wrong, but it just looks a bit menacing. And, sometimes, in my humble opinion, it's not all that bad to get physical with people every now and then. After all, you need to touch something if you want to fix it....