Alter Table Command Rearranges Rows

I noticed that my database was in order based on my primary key column
called 'id' which when from 1 (first) to 6 (last). Today I had to edit
table data which wasn't anything crazy:

team=#ALTER users SET name = 'David' WHERE id = '1';
UPDATE 1

Now when I do a 'SELECT * FROM users' command in PostgreSQL, my row
that I altered column data in has been dropped all the way to the
bottom. This is extremely messy and annoying for me and I was
wondering if this is normal behavior for PostgreSQL? I could
understand that if remove the row and then re-added it, I would expect
it to add a new row to the bottom of the table.

Thanks for any assistance or clarification.

-Carlos