What would you do if you go to a public college and...?

after entering a clroom you notice an empty seat in the front, you have a bada eyesight, therefore you really need it, and when you attempt to seat, someone who's already there stops you and says this seat is reserved. This happened to me, and my reaction was to just go away, but then i was angry because it ruined my cl of that day, i couldn't see nothing. What do you do in this stuation without insult the b.........!? it's a public college!!!!