Concussions are no joke.
I got one in Whistler when I told the internet I'd do a backflip and I tried and belly flopped lol. I hit my chin just right and rung my bell. Didn't realize it until way after the fact.
Also got one while playing rugby. I was tackled and under the ruck and my teammate comes in FULL SPEED and kicks me in the head. That was painful, my other concussions weren't that painful but had more side effects? I guess you could say. Somehow I drove myself home from that practice.