Even The Humblest Parents Have difficult Children

I am sure many parents will relate empathetically with mommy (or daddy) snail.

Look, not all is lost. All you have to do is impress on your kid that they should consider the sage advice I dispense free of charge below on what to do when they think they have found their dream partner. This advice is not original. My friends and I got it from a senior in high school when we were juniors. It is to the everlasting regret of many that they ignored it.
(I) Pick a fight with your boy or girlfriend and see how badly they can behave (it's an experiment to establish a lower bound, recognizable to computational complexity theorists as an "adversary argument"). This shit behavior is what you will have to put up with from time to time in a married life with him/her.
(II) Get to know him/her long enough to visit him/her often at home see how his/her mom treats his/her dad and vice-versa. That's how you will be treated in future. The often bit is essential, so that the parents get so used to your presence they will stop pretending!
(III) At some point, see how your inevitable crude propensities are tolerated -- in other words, you too have to let your guard down and stop faking -- so, try to belch after a meal, swear loudly at the TV when the referee calls a foul the idiot shouldn't have, wear badly fitting clothes on an important date -- then see what happens. If nothing, DROP him/her! They don't care enough about you to stop you from degenerating into the jakun (go back and see what this means in the same "jokes" section) that you may be fated to become without the divine intervention of a loving mate. On the other hand, if he/she becomes a raving looney, DUMP him/her too. What you want for a mate is a bit like a sympathetic correctional facility, mild rebuke followed by community service.