A Sikh places trust only in Vaheguru and Guru Sahib or accomplished Gurmukhs. To trust anyone else, who is entangled in Maya, is not in accordance to Gurmat. Friendships in Gurmat are allowed with Gurmukhs only. Whether Hindu or Muslim, a Sikh sees Vaheguru in all but associates and mingles only with Gurmukh Pyare. There is no hatred in the mind of a Gursikh, for anyone one, be it a Muslim or a Hindu.
There are good Muslims, Hindus and Christians out there and they are worthy of our respect. In day to day interaction at work or college, there is no prohibition in dealing with any person but deep friendships are reserved for Gurmukhs only.
There are sayings of our elders that one should not trust Turks (Muslims) because they tend to deceive. The foundation of these kind of sayings lies in historical incidents whereby, the Mughal and Turk armies won battles through treachery. When Siri Anandpur Sahib was surrounded and besieged by the Mughals but they were unable to penetrate within, they swore by Quran that if Guru Sahib would leave Siri Anandpur Sahib and thereby avoid a conflict, they would not attack them. Guru Sahib did not want to trust them but at the insistence of Sikhs, Guru Sahib agreed. As soon as the Guru Sahib and the Sikh army came out, they were attacked by the Mughals. Guru Sahib has alluded to this incident in Zafarnama. Many such happenings can be found in the history. This is why there has been some distrust towards Muslims.
I have personally met some very pious Pakistani Punjabi Muslims; so I can't say that all of them are bad or all of them are good. Just like any other community, some are good, some are bad and rare ones are pious.
Try to keep friendships with Gurmukhs so that they can inspire you to do Bhagti. Rest of the activities are all in vain.
Kulbir Singh
ਸਤਿਗੁਰਬਚਨਕਮਾਵਣੇਸਚਾਏਹੁਵੀਚਾਰੁ॥