When people comment positively about your game? I recently started posting on indiedb and steam greenlight about my game and got a generally positive reaction. Which is nice. Not that it does much for me, because I'd rather get some feedback that's actionable, but then I've got opportunities for that locally anyway. But it does help with the morale sometimes.
Feedback is so valuable. Be it positive or negative. I find that among a 1000 App Store reviews, there can be a gold nugget worth a fortune. One of my customers wrote a detailed, point by point razor sharp analysis of my game. It is almost as if he was a professional game producer, or senior game journalist. I took his list of issues, and fixed them, making my game twice as good. His user review made me a lot of extra money. I should be paying him. That is why is shake my head when devs say 'do not read forums, it will drain your energy'. Yes, there is a huge pile of 'this game should be free, how dare you charge money' garbage. Wade through it, it will be worth it.
Constructive feedback is the most valuable in general, but getting a positive reaction from people will usually boost your energy and make you feel like you're not wasting time developing your game. Someone has recently suggested we show our game to friends or acquaintances without telling them it's our game, without giving any explanations or instructions. Then observe their reactions first hand. Do they understand real quickly what to do in the game? Is the UI intuitive? Does the game captivate their attention long enough? This also sounds like a good strategy of receiving feedback. We'll try it and let you know how it goes