Hazrat Moulana Ashraf Ali Thanwi (rahmatullahi ‘alaih) once mentioned:

I am always concerned and mindful that at no time should I become the means of causing any inconvenience to others, thereby overstepping the limits of deen. It is for this very reason that while serving some of my elders, I did not carry their shoes, as I felt that they may feel uncomfortable through this action. Due to my causing them the slightest discomfort and inconvenience, I will be overstepping the limits of deen. It is the grace of Allah Ta‘ala that despite my worthlessness, my elders still nevertheless showed me their special attention and consideration. As far as the aspect of khidmat is concerned, serving people in general and making their khidmat is not fardh. However ensuring that others remain in ease and comfort at all times and are not inconvenienced through one’s actions is compulsory. Otherwise bringing discomfort to them while trying to serve them is certainly not khidmat. Hence, if their comfort lies in not serving them, then do not serve them, and if their comfort lies in your serving them then serve them. The point is that we should never cause them any discomfort and inconvenience and should always keep them comfortable and at ease. This is the essence of adab. (Malfoozaat Hakeemul Ummat 7/263)

Source: Ihyaauddeen.co.za