What if we use only main_phase in our test out of all other sub-phases of run_phases in UVM

What will happen if i use only main_phase of sub-phases available for run_phase , here i raise the objection and drop after the driving the stimulus on DUT.
Since sub-phases of run_phases runs parallel or concurrently. Will use of only one sub-phase affect ?
Also if my test-cases are of different flavor , i meant if i have some multi sequences and theses sequences are varied with some having run_phase and some having sub_phases of run_phases only. Whether to use this kind of setup is good or bad?

In reply to ABHISHEKT11:

No sequence has a main or run_phase. Thes are restricted for uvm_components only. Using a mixture of main_phase in one component and run_phase in another one might work without a problem. But it is simply a bad coding style.

In reply to chr_sue:

Thanks for reply , i had corrected my question now. I understand that this is bad coding style. but i still have this questions :

What will happen if i use only main_phase of sub-phases available for run_phase (i.e. reset, configure, shutdown ). Will this affect in anyways?

In reply to ABHISHEKT11:

The problems comes in when you use the main_phase expecting it to start at time 0, then some other code comes in using reset_phase. Then your main_phase gets delayed from time 0. It becomes very difficult to coordinate the use of phases when the code (VIP) comes from many places. By using a sequence hierarchy , you are explicit in the desired flow of your test.

If you do not care about the starting time of main_phase in your simulation, then you are ok.

In reply to tpan:

But you cannot neglect the starting time of the main_phase. If you do so this will modify the behavior you have implemented.