I agree with you Salma. This was brought to Users Notice long ago. Some other Issues are also higlighted below.
It is observed that Users are showing undue haste in selecting the Best Answer. Many Users have requested for a change in Best Answer.
The Best Answer once selected cannot be changed by anyone. It is a System parameter.
Why should one not make haste in selecting the Best Answer? Because once selected, it cannot be changed AND the question gets automatically closed. Other Users then cannot give answers and can only give comments. Many Users do not like to comment as there are no Points for comments, while an Answer gets 5 points.
Also, an answer is clearly read by all. Comments are not read by all. Always wait for 4-5 answers before you select a Best Answer.
Another issue is Flagging an Answer. Many Users flag an Answer to show appreciation. This is incorrect. The idea of flagging is to draw the Moderator's attention to some objectionable matter in the Answer. The Moderator will then review the Answer and make corrections / deletions / editing as required or if satisfied there is no objectionable matter, will "unflag" the flag. So use this (Flagging) option only when you wish to object.
Another issue is using the Tag " ask anjali". This particular tag does not serve any purpose. Why are Tags required? Tags help in searching for a particular Topic. Start SEARCHING quickly checks for topics that you are searching for in the Tags and then gives a list of similar questions. You can give Maximum of 5 Tags for your question. So give Tags wisely, as it will benefit another User looking for Answers to similar question.