What are the reasons that cause pass book of the bank and your bank book not tally?

1 Cheques deposited into the bank but not yet collected2 Amount collected by bank on standing instructions of the concern.3 Interest debited by the bank Direct payment by customers into the bank account3 Cheques distributed but not yet presented for payment4 Bank charges5 Amount paid by the bank on standing instructions of the concern.6 Interest credited by the bank7 Clerical errors

1. Intransit cheques issued to the vendors/customers at the end of month not presenented in bank

2. Error of ommission an amount completly missed or ommitted by accountant in cash book

3. Direct deposited by customers not shown in cash book at closing date.

4. Bank charges deducted by bank on withdrawals or services.

There are many reasons for that, it could be cheques written on my cash book that are not yet cleared from bank, bank charges that are not registered in my cash book, it could also be mistakes from my side or from the bank side، it could be incoming transfers not yet identified in my cash book or it could be cash deposited directly to the bank counter.
And even more.
That is why reconciliation is very important at least once monthly to identify the differences and do all needed corrections.