I have studied bfs, dfs and best first search, but i don't know when bfs is better than best first search. I know the same for bfs and dfs, but have no idea for comparison of best first search with bfs & dfs.

  So, my question is

"When would best first search be worse than breadth first search ?"

(bfs - breadth first search)

I am studying best first search as it compares to BFS (breadth-first search) and DFS (depth-first search), but I don't know when BFS is better than best-first search. So, my question is

When would best-first search be worse than breadth-first search?

This question is one of the back exercises in Artificial Intelligence by Rich & Knight, and it asks for an answer in terms of time & space complexity and allows you to define any heuristic function.