Here is the item again:
Because Simon thinks that he has big, ugly toes, he insists on wearing socks
everywhere that he goes at the beach, in the
shower, or around the house, you will find Simon with his feet covered.
The blank space between goes and at causes a fused sentence. At this spot, there are two complete sentences joined with no punctuation, which makes a major error. He insists on wearing socks everywhere that he goes is a complete sentence. At the beach, in the shower, or around the house, you will find ... begins the next complete sentence.
To fix this problem, you could put a period after goes and capitalize the A for at.