Coworker is dismissive and impolite to new hire, so they take "her" unofficial parking spot

Everyone is going to have bad days, but when your bad day is also someone's first impression of you, they're probably going to think you're just like that all the time, and at the very least, you can't blame them for being cautious in ensuing encounters with you.

Similarly, when you're new, it's always best to follow the rules, whether or not those are written company guidelines or unspoken social agreements and the status quo of the existing team. Coming in and rocking the boat will earn you some sideways glances—at the very least.

These unspoken rules sometimes involve whose parking spot is whose and whether or not they're actually assigned or actually parking spots at all. You'd be foolish to take to parking in a senior member of the team's space… unless they're just so impolite to you when you ask them about parking that you decide you don't really care.