What is the opposite of an insult for the purposes of triggering lasting positive affect? Over the centuries, western cultures have developed dozens of swear words, insults and curse words that are intended to trigger acute negative affect in the recipient. If one particular word does not work, the insulter would typically cycle through the words until he/she finds the one that "strikes a chord" and causes the intended level of emotional distress.

What interests me is that the right insult quickly triggers emotional pain. Unless a person knows how to mitigate the effect, the negative emotion is likely to stay with the person for minutes to hours.

This makes me ask - What are there opposite of insults for the purposes of triggering positive emotion that lingers on afterwards? 

Is there some kind of word or action that instantly triggers positive emotions of equal magnitude? Terms like praise come to mind, but I'm not sure praise is as powerful as insults.
The words we use have no inherent capacity to evoke negative or positive affect.  Instead, how we appraise, reappraise, attend to, and reflect on those words determines our affective response (e.g., Gross, 1998; Siemer, Mauss, &amp; Gross, 2007).

For example, you could tell one person "You are stupid" and he/she might become extremely upset.  You could tell another person the same thing, and he/she would have no affective response.  Similarly, telling someone "You are nice" could make someone very happy or not change his/her mood at all.

So how can we predict who will respond most intensely? Philippe Verduyn  and colleagues (2009; 2011) have looked at predictors of greater emotion response duration, which include:


The salience of the emotion-eliciting event
How you conceptualize your positive/negative affect (joy lasts longer than anger, which lasts longer than fear)
Intensity of the emotion at onset 
Physical reappearances of the emotion-eliciting stimulus
Stimulus-related cognitions with the same valence as the emotion
Social sharing (consistent with Bernard Rimé's work)


How one chooses to regulate their emotions in response to an insult or compliment would also influence emotion reactivity and duration, including tendency to distract oneself from the stimulus (Sheppes et al., 2014) or skill in reappraising the situation (e.g., McRae et al., 2012).

We would also expect depressive rumination (see Susan Nolen-Hoeksema's work) and positive rumination or savoring (e.g., Feldman, Joormann, &amp; Johnson, 2008; Quoidbach, Berry, Hansenne, &amp; Mikolajczak, 2010) to predict intensity of responses to insults and compliments, respectively.

Conclusion

So the point is that there are no special words or phrases that will reliably evoke some level of positive affect.  Instead, the emotional intensity evoked by a stimulus depends on the salience of the stimulus, proximity to the stimulus, and individual differences in emotional responding (i.e., reactivity and regulation; see Gross &amp; Barrett, 2011).  If you take these into account, you can devise more powerful insults and compliments.