I agree that algorithm challenges are kind of pointless when it comes to software engineering but you can hardly blame the OP for doing them given that many companies do value them. And the OP did say they also have their own libraries on github and open source contributions too..
> Now if you don't have any uni friends pulling for you, I really have to think that you might just not be all that friendly, in that you might be standoffish or have some kind of personal trait that is putting people off.
That sounds quite harsh really. Makes me feel sorry for the people you interview who might be perfectly nice people to work with and capable of communicating but don't get hired because they aren't good at making friends or don't have "likeability" as you call it.
> Ego in programmers is the worst, and if someone is mansplaining to me in the interview, I almost never hire them (pet peeve).
Are you assuming that the programmer being interviewed is a man? Thats a bit sexist..