Typically, life keeps me distracted with a bunch of things, so I forget to call my mom and my parents in law. Today, I finally called them and told them that I had bought them some gifts. They felt so happy. They have been giving us a lot, for which I am instinctively grateful. But, to them, I fear that I may seem ungrateful. They feel so happy each time I call them, but I neglect to do so sometimes. We can never show them the same love they show us. Perhaps the love I feel will motivate me better in the future.
Saying both "normally" and "often" is repetitive.
"So I forget" is better than "and I forget" because "so" establishes a relationship between cause and effect, whereas "and" does not.
I don't understand "at my a little surprise"
What you say is true. The older people are never thanked as much as they deserve. They accept it that way because they remember acting the same way when they were young. Don't worry about it too much. Let love be its own reward. Love doesn't demand reciprocity. Love doesn't keep a balance sheet. They don't need your gifts. You yourself are the reward they hoped for.