Whats your most "challenging" Square aspect?

My Sun Squares my Ascendant, first impressions were are not my thing. I sometimes have trouble with authority figures, which didn't do me ANY good when I was younger. I'm better now, I try really hard to be more easy going around others and not come on to strong, which might make some feel unsettled around me. I have Mercury square my Ascendant as well, I blurt out unnecessary things sometimes. I often can't explain myself well enough which leads to me getting misunderstood a lot. When I was really young I would try to say things that would make my parents happy, which wasn't good because now I'm trying to break this habit with others. Lastly I have Pluto square my MC, which means I have to learn to get along with others and not want power for my needs but to benefit others. I think My first two squares I wrote about are my most challenging squares. Cool question and I like the thing that's written up there =)