There are two stories associated with why Brahma is not worshiped among Hindus.
A. The Curse of Saraswati (refer Saraswati Purana)
B. The curse of Shiva (refer Shiva Purana)
A. The curse of Saraswati
Brahma has created a goddess, Saraswati – the goddess of knowledge. Brahma wanted human beings to have the power of knowledge over other animals (rakshasas) so that humanity can prosper. He also wanted a force which can bring more order to this universe. Please note that Brahma is not the father of Saraswati. Saraswati had no mother and Saraswati was not a result of reproduction, she was created to fulfill a need – to direct humanity towards learning and knowledge.
But as soon as he created Saraswati, he was drowned in her beauty.
Saraswati told Brahma that she has no interest in fulfilling bodily desires or needs and that she is happy in her yearning for knowledge. She requested Brahma to leave her alone but Brahma just would not give up. Saraswati moved away from Brahma, first taking the form of a cow. Brahma then followed her as a bull. Saraswati then changed into a mare; Brahma gave chase as a horse. Every time Saraswati turned into a bird or a beast he followed her as the corresponding male equivalent. No matter how hard Brahma tried he could not catch Saraswati in any of her forms.
Saraswati then ran towards Vishnu, asking for advice.
Vishnu said,
Hey Devi, you are the goddess of knowledge. Humanity will learn things with your blessings. But here is the catch. There should be some force which should stop humans from learning too much. If learning goes out of control, humanity may become the instrument of its own destruction
Saraswati asked –
What is that force?
Vishnu said –
“That force is called Kaam. It is lust, love, desire and passion. This force shall make humans blind for a while, so that they give up their chase and eternal thirst for knowledge and engage
Saraswati said
But I can teach how not to be blinded with bodily and carnal desires. Since I am the goddess of knowledge, I have the power to teach everyone this basic thing, don’t I?
Vishnu said
– No devi, you don’t have that power. You can teach and shower your blessings but you have no control on the force of lust which is essential for humanity to foster. If lust is taken away, humanity cannot propagate itself solely with knowledge. Your blessings are required to make humans more intelligent but Kaam is that force which is required to ensure humanity exists in the first place.
Saraswati left but soon she found herself being chased by Brahma. Angered by his display of unbridled passion Saraswati cursed Brahma,
“You have filled the world with longing/lust that is the seed of unhappiness. You have fettered the soul in the flesh. You are not worthy of reverence. May there be hardly any temple or festival in your name.”
So it came to pass that there are only two temples of Brahma in India; one at Pushkar, Rajasthan and the other in Kumbhakonam, Tamil Nadu.
Undaunted by the curse, Brahma continued to cast his lustful looks upon Saraswati. He gave himself a fifth head to enhance his gaze.
B. The curse of Shiva
There is another curse which states that Shiva cursed Brahma when he found him lying to prove his greatness.
Once Vishnu and Brahma had a debate as to who is greater among the two. As the argument became heated, Lord Shiva had to intervene. Shiva took the form of a gigantic Linga, the lingam swept across the universe and both Vishnu and Brahma were told to find the terminal points of the Lingam
Vishnu knew that it is impossible to find the end points of Shiva’s lingam so he didn’t even try.
But Brahma decided to trick Shiva. While he was on the search of the end, he passed the flower of Ketaki at the uppermost part of the lingam. He requested the Ketaki flower to testify before Shiva that Brahma had reached the uppermost part of the lingam and had seen the end. The Ketaki flower agreed. The flower falsely testified that Brahma had seen the end. Lord Shiva became furious at this lie. He then cursed Brahma that he would never be worshipped by any human being. He also cursed the Ketaki flower that it would not be used in any Hindu ritual.
In the Shiva Purana, Shiva appears as a column of fire that raises up into the heavens, and sinks deep down into the nether worlds – not phallus as many people translate the word Linga to. Brahma takes the form of a swan (Hamsa) and flies up to seek the summit of the column, while Vishnu takes the form of a boar (Varaha) and digs deep to find the root of the column. This story is an allegory. It refers to Supreme Knowledge (embodied by the word Shiva and the column of fire) and ways to reach that Knowledge. The Purana says that as Vishnu dug relentlessly and went deeper and deeper, he lost consciousness of the Self and remained in a state of merger (Laya) with the Supreme. Meanwhile, Brahma rode on his Ego (his swan). As the Ego rode higher and higher, the more selfish he became and eventually lied using the Ketaki (Screwpine) flower as false witness.
This entire story is a beautiful allegory on the relationship between Ego and Knowledge – that when ego subsides, what remains is That knowledge.
References
Saraswati, Hindu Goddess
Chapter III. Brahmā and Sarasvati
Why Is Brahma Not Worshipped?