I believe that once parents starts comparing their children to other people's kids, it creates some psychological effects on them. Even in the family, especially the fathers. Whenever your kid faults, instead of meting out the punishment meant for him or her, they end up listing out how a failure the child is and start comparing the child to his or her siblings. This discretion can lead to inferiority complex, hatred, malice and anger which may end up becoming permanent in future.
Its also applicable to grown ups when their parents blames them and calls them failure in life and compare them to the son of one Mr Ojo who is successful or their younger siblings who are doing well. I know siblings who does not see eyeball to eyeball because of such situations. It leads to division in the family, some are sided with their mom while some are siding their dad.
Pls parents, beware of tearing your families apart because of such unintentional mistake in the bid that you are trying to motivate them to become better and hussle like their mates.

Happened to me today.

I only made a friendly reference to our neighbours kid's neat bedroom and how she doesn't remove her Barbie dolls clothes , and the next thing I heard was from my queen was ; 'mummy how could you? you hurt my feelings , you just compared me to XYZ,( drenched in tears like waterfall) . Lord knows I meant well.

The kids we raise today are way too touchy and soft for my liking. I'm not responsible for that, society/ environment does.

OP , As a psychiatrist who can tell between manipulation from psychological effect ... I believe children need periodic remainders whenever they slack , Let's raise intelligent and confident kids , not dummies jare.

Not bully or physically abuse them but guide and correct them to be a better person.

Hmmm...

In child training, it's best to catch them when they are good, more like whenever your child makes a good move commend them,you can also commend little Billy down the street to point out something good to your own kid without neccesarily comparing them.