How far is too far?

So today was co-op day again, and I arrived late so I missed out on most of the chairs. I found myself trying to discourage one of the guys from moving chairs because I wanted to test my strenght. I told him that I counted on being able to do the chairs for a workout--which isn't strictly true because I don't find it very challenging, though I enjoy doing it because other people do find it challenging. And why shouldn't I do it, if it's not hard for me?

However, I did have time to bring a table from storage, and I found--to my amusement--that I could carry the thing by myself. It's a long wooden table, but only half as wide as most folding tables. As far as I can tell, no one else is able to carry one of these by themselves. I know that I've had trouble carrying a full-size table with help from my teenager. But today I took extreme joy in carrying this one to and from storage by myself. I got multiple offers of help from people, and a few strange looks. So I started wondering, am I showing off? Is it bad that I'm doing this? Is it too smug? Is it possible that I should pretend to be weaker than I am so that people won't feel bad? It's an interesting quandry. I see these people at least once a week, their children are friends with my children. Is it being a bad friend if I over-emphasize how much stronger I've become?