Gratitude has been touted as the duct tape of the positive-psychology world--a handy tool that can help sort out nearly any everyday issue that presents itself. Feeling impatient or want to be calmer? Practice gratitude. Aiming to make your brain work better? Count your blessings. Want to nudge your employees to be more successful? Thank them regularly.

There's good reason for this interest in increasing gratitude. A flood of studies indicate that fighting the perpetual human tendency to focus on the negative makes people happier and healthier, but like all good things, a level of sensible moderation and situational awareness is key.

That's the message of a short but thought-provoking talk that researcher Amie Gordon gave at the Greater Good Gratitude Summit. In it she outlines the limits of gratitude and highlights several situations in which saying thank you is likely to backfire. The video version is here, or check out her five top takeaways below.

1. When you're in danger of overdosing

One of the most common prescriptions for increasing gratitude is taking time out regularly to ponder what's good about your life. This is a great idea but, when it comes to counting your blessings, more isn't always better. One study mentioned by Gordon, for instance, showed that thinking about what you have to be grateful for three times a week is less effective than once a week.

Similarly, a long list of things you're thankful for might not give you more joy than a short list. Ask yourself to think up 20 causes for gratitude and you might struggle, leading you to conclude that you don't have enough goodness in your life. Task yourself with coming up with just three, and answers will almost certainly leap to mind, bringing you greater happiness.

2. When it blinds you to your own effort and accomplishments

Thanking others for their contributions is certainly motivating, but you shouldn't take the practice so far that you lose track of your own contributions. Others play a role in all of our successes, but our own hard work counts for a lot, too--don't take thankfulness so far you forget that. Nor should you ever be grateful to the extent that you start to question whether you deserve another person in your life. Gratitude works best when it's paired with self-esteem.

3. When it's applied to the wrong person …

Let's be honest, some people just aren't worth saying thank you to. An abusive partner is the most obvious example, but there are less extreme possibilities too. If your relationship with a romantic partner, friend, or colleague has serious flaws, ditching the connection may serve you better then applying a Band-Aid of additional gratitude.

4. … or situation

The same applies to fixable but flawed relationships. If your conflicts are minor (your employee always forgets to send that weekly status update), a dose of appreciation to keep your perspective and avoid unnecessary irritation might be beneficial. If the issues are more fundamental, getting a little upset will probably be part of the process of fixing them. Focusing on the positive is likely avoidance and will keep you from sorting out the problem.

5. When it'll be seen as sucking up

Gratefulness and unequal-power relationships can be a problematic combination. When your boss thanks you, you feel good. When you thank your boss, she might wonder what you want from her (or whether you really mean what you say or are just currying favor). Keep that in mind before you start thanking people willy-nilly.