Some people subconsciously do that because of insecurities.. bantayi kasagaran potot (not all alright?) mga isog ug pala away kaayo.. it's because they have this height insecurity and want to maybe subconsciously prove to themselves and others that they are not weaker because of that... some may have grown up not having much compared to their friends, cousins etc... so kanang maka palit gani sila ug nindot na butang, ila jud ihambog... I think there's always a little story behind every personality.