Do あなた prefer someone cheering あなた up, または being left alone when you’re in a foul mood?

I don't know. It depends. Sometimes I like to cheered up and sometimes I like to be left alone. But usually people leave me alone when I want to be cheered up and bug me when I want to be left alone to mope and be depressed.

Inasmuch as someone letting me just vent to them can be considered cheering me up, I prefer that.

Depends on what happened really. Typically I like to be left alone tho.

It depends. I always appreciate the gesture and some genuine encouragement can go a long way but there are the times where I very much prefer being left alone to work things out. Repeating the same stuff again and again can also turn out to be annoying even with good intentions behind. Nonetheless, I remain appreciative of those and do not hold anything against 発言しました person of course !!!!