Love vs. spoiling
Giving your dog love, cuddles, treats, and affection is one thing. Giving your dog whatever they want, whenever they want it, is spoiling them. Why does it matter if you give your dog everything for which they ask? Compare the situation to the raising of a child. If you love your child, you'll still create boundaries for them. You won't simply give in to temper tantrums and demands for toys and candy because, as a parent, you'll understand that this creates a problem: a spoiled child who doesn't know or accept any boundaries.
The same thing happens with dogs. Dogs need boundaries, otherwise they become anxious and agitated, eventually acting out with bad behaviour.
If you feed your dog at their dish every day, then suddenly feed them from the table another day, they'll be confused. In fact, they'll probably beg for food on the third day, since they'll expect you to feed them from the table again. Inconsistency makes training very difficult and will confuse your pet, so be consistent with your rules.
Puppies grow up
A cute, begging puppy or one that jumps up at you every time you come in the room is adorable. A full-grown dog that acts this way, however, is a nuisance to you and those around you. Plus, it can be dangerous if your spoiled dog thinks they can jump up on a small child. By allowing your dog to jump up, you are essentially spoiling them, and excusing or dismissing bad behaviour instead of taking control of the situation. By rewarding your dog with attention when they jump up, you are telling them it's okay to misbehave. This will only make it harder for you in the long run when you want your dog to do as they're told.