I've played dota for a while and used to feel this way. It's still not something I'd recommend to get smarter, but if you feel like it's making you lazy try staying focused while you're dead. Personally I just think about what I/my team could have done differently (or if maybe my death was a good trade). After minute 30 or so you spend upwards of a minute dead, if you just go and check reddit or whatever it just reinforces hard thinking -> extreme mind candy (or at least, it did for me).

Plus you'll probably improve, I rose a few ranks after starting to do this.