"Not all guys are outright about their interest, but there are certain signs you can definitely look for. If you've developed an inside joke, that's for sure a good thing. How polite is he being? Is he buying drinks? Offering his seat? Walking you home/to the train? Is he staying out way later than he should? Generally trying to make sure you're enjoying yourself? Is it super easy to convince him to get one more round when he has to wake up for work at seven? He might be miserable the next day...but he probably won't mind." Brady O.
"If the guy doesn't say something and take the check off the table to pay, it's probably fair to assume that you're going Dutch. There are different reasons that a guy might not pick up the tab (some that might not have anything to do with you), but if you're into him, avoid looking too disappointed. You don't want him to think you expected it." —Josh F.
I once worked with a colleague who was incredibly dismissive and known for not responding to emails, phone calls or text messages. In addition to being non-responsive, the team member was rude. I worked with him for years and deeply disliked his lack of accountability. At some point, our relationship reached a tipping point, and I actively prayed either he or I would find a new job.