Personally, I like scanline filters for games that were released in before HD and I find it makes the games feel... I don't know, more natural looking? However, you really shouldn't care what other people like and if its something you find yourself not enjoying I don't really see why you'd worry about it. Do what you like and what makes you comfortable. You'll never catch me stretching a GBA rom to a wide aspect ratio but if that's something YOU enjoy doing then you should do that. Emulators these days add so many options and toggles to play with and you're doing yourself a disservice not customizing everything to your own personal enjoyment. Play games the way you want to play them.