Honestly, if Oliver is shirtless and speaks with Kwanten's Australian accent, does Jess really need to have anything in common with him? Nonetheless, we have seen friendship blossom to love, as chemistry has given way to concrete feelings.
As a result, Jess went out with various guys throughout New Girl, though many of them were nothing more than just a one-night stand.
Another example from Jess's side is when Nick announced his moving in with his ex-girlfriend, soon after they got back together, and Jess hid the keys of the truck carrying his things so that he could have a last chance to reconsider his choice.