Odd Mic Problems

lately i’ve been messing around in Garry’s Mod. So i was like “hmm i should use my inbuilt mic” so i go use it Garry’s Mod and people were saying “Aggg stop using your mic its terrible” so i mess in the settings of my pc and test it on skype with my friends and they say its fine and they don’t know what can be the problem. so i test it in the voice settings in Garry’s Mod and it sounds perfrect. i don’t know what the problem could be. any help?

maybe because it is possibly bad? (like echoing, your voice is unclear, background noise, etc) This can be a opinion thing though.