You'd think it would be easy spot when you're working too hard--long hours, painful wake-ups and general exhaustion are sure tip-offs, right? The funny thing is, our bodies and minds have a funny way of adjusting to the demands we place on them, at least for awhile.

As your hours creep up and the pressure gradually intensifies, you may end up feeling like you're flying (or at least grinding it out) until one day, burnout hits with a vengeance and your health or your sanity crumbles. Rather than get to that point, wouldn't it be good if you could keep an eye out for early warning signs that your schedule and stress levels are starting to get out of whack so you can make adjustments before you collapse?

Joel Peterson, chairman of JetBlue Airways and a longtime Stanford business school professor, has your back on this one. Obviously quite a busy guy himself, Peterson recently offered a list of tell-tale warning signs you're working yourself too hard in his LinkedIn Influencer column. Here are a few of them:

1. You're not as nice as you want to be. 

Before your energy levels nosedive and your brain starts meltdown, you may find that you lose your ability to play nice with others, Peterson cautions. His advice: "If you find yourself berating waiters, flight attendants, or reservations agents, make a habit of taking an extra minute during every interaction to thank them--and be specific, if possible. In trying to cheer up those who are doing tough jobs, you might also boost your own spirits."

2. Your mind is always racing. 

Having plenty of ideas is great, but living on a mental hamster wheel? Not so much. "You think the root of your stress is that you spend all of your time in a state of intense focus. But really, most people under stress are re-plowing the same field over and over. They confuse this obsessing with focus, but it's really the opposite," Peterson cautions.

If on closer examination you realize your mind is chasing its own tail, get some space to reset, consider your priorities and give your brain a chance to approach problems from a fresh perspective.

3. You throw yourself a pity party. 

Let's be honest, if you're a First World business owner, you might have some serious stress, but you are probably far, far from the worst off on planet earth. If you're working hard, it can be easy to forget to count your blessings and keep your sense of perspective, however.

"If you find yourself feeling under-appreciated, change your surroundings--or, at a minimum, change your attitude. Replace self-pity with gratitude, or better yet, find a way to serve those less fortunate than you. In the process, you'll discover you have a lot to be grateful for," writes Peterson.

4. You don't live in the moment. 

Does this sound familiar? "You reminisce, telling stories of past glories. Or you await the future, unable to really start living until a certain goal is behind you. Both of these are signals that you're living outside the present, a habit that only leads to more stress," Peterson writes. "Being present in the moment, enjoying the conversation, the meeting, the people and the challenges as they come up will reduce stress."

5. You're constantly late.

OK, some of us have a natural tendency to lose track of time no matter how relaxed (or stressed) we are, but if you find you're running late more often than is usual for you, that's probably a warning sign you're working too hard. Peterson suggests you fight back: "Make a commitment that you'll be five minutes early to every meeting and every event, and then tell others about it as a way forcing you to curtail the activities that are making you late."

What are your personal warning signs you're pushing yourself too hard?