I went out to run a quick errand today, and when I got on the bus there was a woman sitting in the side-facing seats just behind the driver with a baby carriage in front of her. I happened to sit in the first forward-facing seat directly behind them. After I sat down I looked up and saw a tan-and-black pug staring at me from the carriage. (In describing it, I realize now that I should have taken a picture of it.)
It didn't exactly surprise me, since people do weird stuff all the time, but it did catch me by surprise a bit. I didn't think non-service animals were allowed on T trains and buses, but a look at their website shows that I'm wrong, though it does say it's at the discretion of the operator. I don't know if that dog gets chauffeured around in that baby carriage all the time, or if it's just used for T trips.